Complex sentence: After the Battle of Lexington in 1775, British General Thomas Gage occupied Boston, Massachusetts, and upon negotiating with the town committee, Gage agreed to let the inhabitants of Boston leave town with their families and effects if they surrendered all arms.
Split into simpler sentences: After the Battle of Lexington in 1775, British General Thomas Gage occupied Boston, Massachusetts. After negotiating with the town committee, Gage agreed to let the inhabitants of Boston leave town with their families and effects, if they surrendered all arms.