What was Alexander McGillivray's role in negotiations with the Creek tribe as noted in the nonfiction book, The World Turned Upside Down: Indian Voices from Early America?

Alexander McGillivray, half-Scottish and half-Indian, acted as an intermediary between white and Indian cultures. He helped the Creek Indians negotiate with Spain and later with America. Unfortunately, he died of illness at a young age, leaving the Creek Indians somewhat leaderless.