Complex sentence: Throughout his decades-long career, Weiser built on his knowledge of Native American languages and culture to become a key player in treaty negotiations, land purchases, and the formulation of Pennsylvania's policies towards Native Americans.
Split into simpler sentences: Throughout his decades-long career, Weiser built on his knowledge of Native American languages and culture. He was a key player in treaty negotiations, land purchases, and the formulation of Pennsylvania's policies towards Native Americans.