Complex sentence: During the American Revolution, there was movement to create a state beyond the Alleghenies, and, in 1776, a petition for the establishment of "Westsylvania" was presented to Congress, on the grounds that the mountains made an almost impassable barrier on the east.
Split into simpler sentences: During the American Revolution, there was movement to create a state beyond the Alleghenies. In 1776, settlers presented a petition for the establishment of "Westsylvania" to Congress, on the grounds that the mountains made an almost impassable barrier on the east.