He became grand sachem after sachem Tatobem was killed in 1632. The Mohegans under the sachem Uncas rebelled against the Pequot's authority.2 Sassacus and the Pequots were defeated by the English along their Mohegan allies in the Pequot War. Sassacus fled to what he thought was safety among the Mohawks. Sassacus was murdered by the Mohawks in present day New York, and his scalp was sent to the British as a symbolic offering of friendship with the Connecticut Colony.3
^ Vaughan, Alden T. (1995). New England Frontier: Puritans and Indians, 1620-1675, p. 150. University of Oklahoma Press. ISBN 080612718X, ISBN 9780806127187.
References
Oberg, Michael Leroy, Uncas, First of the Mohegans, 2003, ISBN 0801438772