Final answer:
Between 1617 and 1619, Massasoit witnessed the devastating effects of diseases brought by European traders and fishermen on his people.
Step-by-step explanation:
During the time period between 1617 and 1619, Massasoit, the leader of the Wampanoag people, saw his people being greatly affected by diseases brought over by European traders and fishermen. These diseases, such as smallpox, had a devastating impact on the native population and caused many deaths.
Learn more about impact of diseases on Native American populations