Chelsea in the 17th Century

​European fishermen, using temporary stations on the coast to process their catch, sparked epidemics among tribes, especially those living along the waterways. This caused political turmoil between tribes. To the north, the Tarratine tribe (present day Maine) raided the neighboring Penobscot tribe (present day New Hampshire). In 1615, Nanepashemet sent his Pawtucket warriors to assist their Penobscot allies. When the Tarratines turned their ire on Nanepasemet, the leader and his family took shelter in a fort on the Mystic River.

This period of hiding proved to be fortuitous for the family. Between 1614 and 1619 three epidemics of European diseases struck the Pawtucket. The death toll was staggering. Some contemporary historians believe the mortality rate among the Native people was as high as 90%. The family's period of seclusion served as a kind of quarantine and they survived unscathed.

But the Tarrantines eventually secured their revenge. In 1619, New Moon, the great Sachem Nanepashemet, was killed by the Tarratines.

Leadership fell to his widow, Saunkskwa Mysticke (also called “Squaw Sachem” of Mysticke) (c. 1590-1650 or 1667). She was the primary authority among the native people of the area now called Chelsea when Samuel Maverick builds his fort on the shores of Winnisimmet.

After the death of Nanepashemet the Confederation fractured with some of the bands in extended territories breaking off. Nevertheless, Saunkskwa Mysticke oversaw significant areas along the Charles and Mystic Rivers and up the North Shore. Through a time of extraordinary upheaval, Saunkskwa Mysticke led her people, building alliances with other tribes through the marriages of her children and with the English settlers through the strategic deeding of land.

Saunkskwa Mysticke and Nanepashemet had three sons, Wonohaquaham (John) (1608-1633), Montowampate (James) (xx - 1633), and Wenepoykin (George) (1616 or 1620 - 1684), and one daughter, Yawata (Abigail) (1614 - 1685).

In 1633, the three sons of Saunkskwa Mysticke fell gravely ill with smallpox. Wonohaquaham (Sagamore John) was only aged 25 and had already witnessed waves of European diseases that killed his kinfolk but left the colonists mostly unscathed. Like some other Native people of this time he came to associate surviving these new illnesses with the power of the Englishman's god. On his deathbed Wonohaquaham converted to Christianity, prayed his sons might be spared and put them into the care of the colonists. Montowampate (Sagamore James), like his elder brother, perished. Teenaged youngest brother Wenepoykin (Sagamore George) survived but was left with a horrible facial disfigurement.

At this time, the primacy of colonial authority of the area was asserting itself. In 1634, the court of the Massachusetts Bay colony ordered that the areas of Winnisimmet, (present day Chelsea) Rumney Marsh and Pullen Point (present day Revere) to be part of Boston and the borders of these places were fixed. Two ferries were now operating to carry people and cargo across the waterway from Winnisimmet to the port of Boston. A year later, in 1635, Richard Bellingham, the newly elected Deputy Governor of Massachusetts Bay Colony, purchased Winnisimmet from Samuel Maverick.