Wordsmith mentions Massasoit, sachem of the Wampanoags, who was friendly towards the Pilgrims. The Wampanoags had lost nine tenths of their people as result of a disease, probably transmitted to them by sailors of fishing vessels that had visited before the Pilgrims arrived. As a result,
the Wampanoags feared attack by the Narragansetts, and hoped to have the Pilgrims help them resist the Narragansetts. Except for their weakness, the Wampanoags would very likely have wiped the Pilgrims out.

Here is a URL about Massasoit:
http://freepages.genealogy.rootsweb.com/~massasoit/book03.htm