Although some estimates have ranged as high as 20,000, the combined total of all of the Mattabesic tribes in western Connecticut in 1600 was probably near 10,000 living in as many as 60 villages. Just before the arrival of the first English colonists at Plymouth, Massachusetts in 1620, three major epidemics swept across New England and the Canadian Maritimes. Since the migration of several thousand Pequot-Mohegan into eastern Connecticut at this time masked the losses of the original tribes, the effect on the native population in Connecticut is not entirely clear. The best guess is there were about 5,000 Mattabesic in 1620. Contact with the Dutch and English became frequent after this, and disease took a steady toll - smallpox in 1633-35 being a major killer.

In the years immediately following the Pequot War (1637), the lands of the Mattabesic tribes adjoining the Connecticut River and the coastline of western Connecticut were taken by English settlement. There was little warfare involved with this displacement. A few tribes were conquered and incorporated into the Mohegan, but as a rule, the others separated into small groups and moved west to the Housatonic Valley and were absorbed by the Paugussett tribes. By 1700 the native population in western Connecticut had fallen to less than 1,000, but because settlement was slow to expand into this area, the Mattabesic still controlled over 500,000 acres. This, of course, did not last very long. By 1800 encroachment, fraud, intermarriage, disease, and migration had reduced the Mattabesic to 77 people living on 1,700 acres at the tiny reservations at Golden Hill, Turkey Hill, Naugatuck, and Schaghticoke. After another century of attrition, there were only 20 Mattabesic.

Currently, the Golden Hill Paugussett and Schaghticoke are recognized only by the state of Connecticut and not the federal government. Golden Hill at Trumbull, Connecticut is the oldest Indian reservation in the United States, but its size has been steadily reduced over the years until there are only 0.26 acres. In 1979 the Golden Hill Paugussett, who have a membership of 120, used a grant from the Department of Housing and Urban Affairs to purchase 108 acres near Colchester, Connecticut. The Schaghticoke (or Scaticook meaning "branching waters place" and NOT to be confused with the other Schaghticoke in New York which was Mahican) have a 400 acre reservation near Kent, Connecticut. Their 350 members are descendants from a mix of Paugussett and several other Mattabesic tribes. Other descendants of the Mattabesic can still be found among the Stockbridge and Brotherton Indians in northern Wisconsin.

Hidden behind Long Island to the south, the Mattabesic did not have contact with Europeans until Dutch fur traders from New Netherlands (the Hudson Valley in New York) began to explore the southern coast of New England after 1610. They first met the Paugussett and Peaquanock at the mouth of the Housatonic River and soon afterwards began to trade with the other Mattabesic tribes to the east along the coast and the lower Connecticut River. By 1622 the Dutch had built a permanent trading post near present-day Hartford from which they intended to trade with all of the tribes in Connecticut. However, the Pequot had other ambitions. Determined to dominate the area's trade, they attacked some Mattabesic near the trading post. The Dutch seized a Pequot sachem and held him for ransom and, it can be presumed, promises of better behavior. However, the Dutch took the ransom and then killed their prisoner, after which, the Pequot retaliated by burning down the post. Ultimately, for purposes of mutual economic benefit, both sides decided it was best to "kiss and make up," but afterwards, the Dutch made no further attempts to prevent the Pequot's domination of the other tribes in the area.

The highly-organized Pequot immediately set about their work. Later that same year, they fought a war with the Narragansett to seize territory in western Rhode Island and to keep this powerful rival away from the Dutch. Having accomplished this, they paddled across Long Island Sound to subdue the Metoac to gain control of the wampum trade and then expanded north and west to subjugate several small Nipmuc and Mattabesic tribes in Connecticut. While the Dutch looked the other way at the Pequot conquests, they were becoming concerned about the possibility of competition from the new English colony in eastern Massachusetts. In 1627 they sent a representative to Plymouth. The result was a treaty with the English giving the Dutch a trade monopoly along the southern coast of New England and Connecticut Valley. This agreement lasted for only three years until the more militant Puritans began settling in Massachusetts. As the balance of power shifted in favor of the English, the treaty was disregarded. In 1633 Boston traders established a trading post at Windsor, Connecticut which, because it was just upstream from the Dutch at Hartford, intercepted most of the furs from the north which formerly had been going to the Dutch.

Turning to the Pequot for support against the English, the Dutch purchased land from them (which actually belonged to the Mattabesic) and built a fortified trading post (House of Good Hope). In 1635 the English countered with a fort of their own (Saybrook) at the mouth of the Connecticut, and the Dutch were cut-off. English settlement of Connecticut began the following year. Many of the Mattabesic along the river (including a faction of the Pequot who would separate to become the Mohegan) welcomed the English as an opportunity to rid themselves of the Pequot thereby setting the stage for the Pequot War (1637). The first blow was actually struck by epidemic. Beginning in 1633 among the tribes in eastern Massachusetts, smallpox spread through the native populations of New England and reached Connecticut in 1634. Ignoring their losses to epidemic, the Pequot met the new English settlement along the Connecticut first with threats and then small-scale violence. An English retaliatory raid during the summer of 1636 escalated the confrontation to open warfare the following spring.

Although reduced by smallpox and the recent defection of the Mohegan, the Pequot commanded the allegiance of 26 tribes and were still formidable. However, in May of 1637, a combined force of English, Mohegan, and Narragansett commanded by Captain John Mason destroyed the main Pequot fort at Mystic and massacred 700 of its inhabitants. After this defeat, many of the Pequot's Mattabesic, Metoac, and Nipmuc allies suddenly switched sides, and the Pequot were forced to abandon their villages and flee west towards the Dutch settlements on the Hudson. Few of them made it. On July 13th, Mason and the Mohegan caught up with a large group of Pequot and their sachem Sassacus who had found refuge at the Pequannock village of Sasqua (Fairfield, Connecticut). Mason and his men surrounded the Peaquanock fort which was hidden in a swamp, but after some negotiations, 200 Pequannock (mostly women and children) were allowed to leave. However, the Pequot were well-aware of the fate awaiting them and refused to surrender.

In the battle which followed, 20 Pequot warriors were killed. Another 60, including their sachem Sassacus, escaped and managed to reach the Mohawk. The Mohawk killed Sassacus and sent his head to the General Court at Hartford as a token of their friendship with the English. The Pequot War ended with the near annihilation of the Pequot as English soldiers and their native allies hunted down the last survivors. Those not killed were either sold as slaves to the West Indies or placed under the jurisdiction of the Mohegan who did not treat them well. In general, the Mattabesic were pleased by the outcome of war but did not realize at first they had exchanged one master for another far more dangerous. Immediately after the war, English settlement swept down the length of the Connecticut Valley and then west along the shore of Long Island Sound: New Haven 1638; Bridgeport 1639; and Stamford 1641. For the Mattabesic, Paugussett, and other tribes in the area, the native allies of the English soon proved as aggressive and dominating as the Pequot.

The Narragansett invaded the eastern end of Long Island and conquered the Metoac tribes to assume the Pequot's former role in the wampum trade. However, the Mohegan were even more dangerous. Backed by their alliance with the English, they began to threaten many of the neighboring Mattabesic and Nipmuc and forced them to pay tribute. Even the Narragansett became alarmed at the growing power of the Mohegan and in 1640 formed an alliance with the Tunxis and Pocumtuc to oppose them. Meanwhile, the English colonists in New England had become divided over politics and religion between the Puritans (Mohegan allies) and the dissident settlements of Roger Williams in Rhode Island (Narragansett allies). When the English colonies in Connecticut and Massachusetts joined forces in 1643 with the formation of the New England Confederation, Rhode Island was excluded, and the Puritans had succeeded in isolating Williams and the Narragansett. At this point, the Narragansett decided to act on their own. They attacked the Mohegan but were defeated in a decisive battle at Shetucket.

After this, the Mohegan were clearly the dominant tribe in southern New England and acted as "enforcers" to insure that English settlement could push west from the Connecticut River unopposed. For the most part, the tiny Mattabesic tribes were helpless against the combination of the English and Mohegan. This became especially apparent after some Mattabesic warriors from western Connecticut tribes joined the Wappinger against the Dutch (Wappinger War 1643-45). Although the Dutch were nearly overwhelmed at the start of this conflict, things changed dramatically after two companies of Mohegan scouts and Connecticut colonists commanded by Captain John Underhill joined the fighting in 1644. A combined Dutch-English attack on a Siwanoy village near Greenwich, Connecticut that year killed almost 700 people, exactly the same number as the much better known massacre of the Pequot at Mystic seven years earlier.

Before a peace was signed in 1645, at least 1,600 Wappinger and their allies had been killed. After this experience, very few Mattabesic were willing to challenge either the English or the Mohegan. The Massaco, conquered by Mohegan in 1654 and forced to pay tribute, were eventually absorbed by the Mohegan who then sold the Massaco lands to English settlers. Several Mattabesic groups near the Massachusetts border (Newashe, Peskantuk, Poquonock, and Sicaog) tried to break free by attaching themselves to the Pocumtuc in western Massachusetts, who since they were at war with the Mohawk, needed every ally they could find. The Mohegan, however, kept pressuring these tribes which led an exchange of raids between the Mohegan and Pocumtuc during the winter of 1658-59. When the Mohawk finally forced the Pocumtuc to abandon the Connecticut River in 1665, many of their Mattabesic allies retreated east with them and ultimately ended up as part of the Abenaki in northern New England.

However, the other Mattabesic tribes in central Connecticut did not fight and, as they were dispossessed by settlement, began to move west towards the Housatonic Valley. For the most part, there was no exodus of tribal units. Instead, the Mattabesic nearer to the Connecticut River tended to melt away by separating into family units which were then absorbed by the Paugussett and other Mattabesic along the Housatonic, a rugged area which remained relatively unsettled until the 1700s. Other groups collected for a time in mixed native communities at Farmington and Naugatuck. After 1637 English settlement had also extended down the coast and taken land from the Paugussett and Peaquanock at the mouth of the Housatonic. By 1658 the settlements at Fairfield and Stratford had taken so much land, the Peaquanock petitioned the General Court at Hartford to set aside some land for them alone before the colonists took it all. The following year Connecticut created Golden Hill, the first Indian reservation in the United States.

With the exception a few Podunk warriors, the Mattabesic took no part in the general uprising in Massachusetts and Rhode Island known as the King Philip's War (1675-76). Many of the southern New England tribes disappeared entirely or left the region as a result of this conflict. By 1680 there were only 1,000 Mattabesic left in Connecticut, at least half of whom were members of the Housatonic tribes (Paugussett, Peaquanock, Potatuck, and Weantinock). As white encroachment continued, the General Court in 1680 established two additional 100 acre reservations for the Paugussett: Coram Hill (Shelton) and Turkey Hill (Orange). In addition to the three small reserves, several mixed Mattabesic communities, such as the Paugussett village at Naugatuck and Tunxis settlement at Farmington, were still managing to maintain themselves on a rapidly shrinking land base. Only the Weantinock and Potatuck in extreme west and northwest portion of Connecticut had retained anything approaching their original territory. However, even these small holdings quickly slipped away and passed into white ownership.

During the next century, almost all of the Mattabesic lands in Connecticut would either sold or taken over by the state - in many cases without native knowledge or consent. Even when the transfers were legal, the circumstances were often questionable since the native signatures appearing on the deeds show a clear pattern of increasingly sloppy signatures and the probable use of alcohol. Located near the English settlements at the mouth of the Housatonic, the Pequannock and Paugussett were the first to feel the pressure. Between 1680 and 1750, a combination of fraud, harassment, and encroachment forced many of the native families at the Golden Hill reservation to leave. Some moved north to the native settlement of Lonetown near Redding. One group, the Ramapo (Peaquanock), apparently ended up in the mountains of northern New Jersey which still bear their name. From the beginning, the Paugussett never liked the land at Coram Hill because it was stoney and poor for growing corn. They sold 20 acres in 1714 to a white man who apparently liked rocks and the remainder by 1735. However, Golden Hill was a more valuable land, and by 1760 the four families who had stubbornly refused to leave had only six of the original 80 acres, all but 1/2 acre of which had already been allotted to colonists under the presumption the Golden Hill Indians would soon be extinct.

Unfortunately, some whites did not wait for extinction, and in August of 1763, they destroyed the remaining wigwam and forced the last two families to leave. The Connecticut General Assembly appointed a committee to deal with the situation. Its first recommendation was that the land be given to the colonists and the Golden Hill Paugusset and Peaquanock be compensated with other land. This was rejected. A second report suggested returning all eighty acres to the Paugussett, but for obvious reasons, this also failed to gain approval. Finally, after two years of deliberation, twenty of the original eighty acres were returned in 1765 to the Paugussett: twelve acres (Nimrod Lot) and eight acres (Rocky Hill Lot - the name leaves little doubt why they got this piece of land). The last Paugussett lands at Naugatuck were sold in 1812, and the Turkey Hill Reserve went on the block in 1826. Currently, the Golden Hill Reservation consists of exactly 0.26 acre - barely enough for a single house.

Other than token payments, all that the Mattabesic tribes in Connecticut usually received for their land was the opportunity to become Christians. Shortly after settlement, English missionaries had started working among the Mattabesic. As a general rule, the eastern Mattabesic groups which had avoided absorption by the Mohegan or Pocumtuc (Hammonasset, Menunkatuc, Quinnipiac, Podunk, Tunxis, Wangunk) gathered near Farmington which, by 1770, had became a mostly Christian community. In time these mixed communities evolved into the Brother Towns (later known as the Brotherton) and also included Mohegan, Narragansett, Niantic, Pequot, Massachuset, Metoac, and even a few Paugussett. However, Christian or traditional, Native Americans were no longer welcome in Connecticut, and feeling this, some of the converts left for the Christian Mahican communities near Stockbridge in western Massachusetts. At the invitation of the Oneida in 1788, the Mahican minister Samuel Occum left with 250 Brotherton Indians from Connecticut and Long Island and resettled in New York.

West of Connecticut River and north of the coastal settlements at Fairfield and Stratford, the Weantinock and Potatuck were protected from the advance of "civilization" until 1700, but afterwards were forced to either sell or deed away almost all of their land. The first Weantinock cession occurred in 1703 and the Potatuck did likewise two years later. By 1729 Weantinock had surrendered most of their original territory. In 1731 a large group of the Christian Pequannock and Paugussett left Naugatuck under Gideon Mauwee (a.k.a Mahwee or Maweseman) to settle at the old Weantinock hunting camp on the Housatonic at Schaghticoke (Kent, Connecticut). Within the next few years, the settlement at Schaghticoke became a refuge for Christians from the western Mattabesic groups (Paugussett, Pequannock, Potatuck, Weantinock). The Mattabesic still practicing their traditional religion, for the most part, remained at Naugatuck, Golden Hill, and Turkey Hill. By 1740 Schaghticoke had a mixed population of almost 600, but the residents were dissatisfied with their Connecticut missionaries and turned instead to the Moravians at Shekomeko just across the border in New York.

In 1743 a Moravian mission was established at Pachgatgoch (or Pishgatagotch - the German version of Schaghticoke). Schaghticoke in 1744 had almost 2,000 acres, and in 1748 the Peaquanock at Lonetown exchanged the last of their lands at Redding for 200 acres bordering Schaghticoke. Unfortunately, Connecticut's colonists did not approve of the Moravian version of Christianity, and many of them wanted both the mission and reservation closed. Because of this, there were continuous problems with squatters and encroachment, and in both 1749 and 1751, the Schaghticoke deeded away more of their land. To slow this, Connecticut formally established the Schaghticoke reservation in 1752, but the problem continued. During 1758-59 the Potatuck sold their remaining lands at Newtown and Woodbury, but by this time nearly all of them were at Schaghticoke which had become overcrowded. Some Potatuck left in 1762 and followed the Housatonic north to the Mahican villages near Stockbridge. The situation in Massachusetts was little different. In 1786 the last group of Stockbridge (including the Mattabesic living among them) left and resettled with the Oneida in New York where the Mattabesic contingent was reunited with those who had left with the Brotherton. In 1822 the Stockbridge and Brotherton, as well as their Oneida hosts, were forced to move again this time to northern Wisconsin where their descendents still live today.

When the Moravian mission closed, some of the Schaghticoke migrated to the Moravian mission at Gnadenhuetten near Bethlehem, Pennsylvania. Apparently, they were never comfortable in this new location, and by 1790 most had returned. However, by this time there were few Mattabesic left in Connecticut. In 1798 the population at Schaghticoke was only 67, and by 1801 it had fallen to 35. They still had 1,200-1,500 acres, but only because most of it was unsuitable for farming. The State of Connecticut took over the management of their land and, in caring for its charges, managed to reduce Schaghticoke to its present size of 400 acres. The Schaghticoke have a lawsuit pending over this. The census of 1850 listed only 400 Native Americans in Connecticut, all Mohegan. By 1910 there were only 22 Mohegan, 20 Mattabesic, and 66 Pequot (108 total), and it would seem that the original residents of Connecticut had just about completed their "ride into the sunset." However, the report of their demise proved somewhat premature. The 1990 census listed 6,634 people in Connecticut who identified themselves as Native Americans.

Middletown occupies the site of an Indian village, Mattabesec or Mattabesett (from Massa-sepues-et, ” at a great rivulet or brook”), the principal village of the Mattabesec Indians, an Algonquian tribe which included the Wongunk, Pyquaug and Montowese Indians and seems to have had jurisdiction over the whole of south-western Connecticut