Uncas then removed to the interior and placed himself at the head of the Mohegan clans who occupied lands east of the Connecticut river, and west of the great Pequot River now known as the Thames. While Sassacus traded with the Dutch, Uncas developed alliances with the English. War eventually broke out between the English and the Pequot after the murder of John Oldham in 1636 and the punitive expedition by John Endicott. In May of 1637, Uncas with seventy Mohegan warriors joined ninety Englishmen under the command of Capt. John Mason in the famous expedition against the Pequots, sailing down the Connecticut river to Saybrook, then to Narragansett Bay and attacking the Pequots from the eastward. In a series of bloody battles, Uncas and Mason brought the power of the great Pequot nation to an end. Sassacus and a party of thirty to forty men did manage to escape to the Mohawks, but their new hosts put them all to death, sending their scalps to the English.
After the distruction of the Pequot Nation, the Narragansetts became emboldened and thought to extend their borders into the previous domain of their neighbors. Led by their Sachem, Miantonomo, who had a strong dislike for Uncas, a force of five to six hundred warriors marched against the Mohegans. In the summer of 1643, the Mohegans and Narragansetts met on the "Great Plain". Uncas had perhaps half as many warriors as the Narragansetts. On the approach of the enemy, "Uncas sent forward a messenger, desiring a parley with Miantonomo, which was granted, and the two chiefs met on the plain, between their respective armies. Uncas then proposed that the fortunes of the day should be decided by themselves in single combat, and the lives of their warriors spared. His proposition was thus expressed: 'Let us two fight it out; If you kill me, my men shall be yours; but if I kill you, your men shall be mine.'
Miantonomo, who seems to have suspected some crafty manoeuvre, in this unusual proposition, replied disdainfully, 'My men came to fight, and they shall fight.' Uncas immediately gave a pre-concerted signal to his followers, by falling flat upon his face to the ground. They, being all prepared with bent bows, instantly discharged a shower of arrows upon the enemy, and raising the battle yell, rushed forward with their tomahawks, their chieftain starting up and leading the onset. The Narragansetts, who were carelessly awaiting the result of the conference, and not expecting that the Mohegans would venture to fight at all with such inferior force, were taken by surprise; and after a short and confused attempt at resistance, were put to flight."**
The battle lasted but a moment and Miantonomo, deserted by his people and over-weighted by an English corselet, was caught, after a long chase, by Uncas and one of his sachems. Uncas turned Miantonomo over to the English authorities for trial. The Connecticut counselors directed that Miantonomo be given up to Uncas for execution outside of the commonwealth's jurisdiction. The Narragansett chief was delivered to the custody of Uncas. When the Mohegans had reached the scene of the battle, Uncas gave a signal to his brother, Wawequa, whose place was just behind the captive. Wawaqua at once sank his hatchet into Miantonomo's brain, killing him instantly.
At the start of King Philip's war, Uncas was too old to take active part but his son, Owaneco, with several hundred Mohegans rendered valuable assistance to the colonists in their fight against the unfriendly Indians. Attawanhood (Joshua), another son, with a band of thirty Indians scoured the woods in the route of the retreating foe, and took active part in the conflict.
Major John Mason, one of the original founders of Norwich, refers to Uncas, "He was a great friend and did us much service".
Uncas died in 1682/3, having been sachem of the Mohegans since the overthrow of the Pequots in 1637.
* History of Norwich, Connecticut: From its possesion by the Indians to the year 1866, by Frances Manwaring Caulkins, 1866, page 30
** IBID, page 32