Complex sentence: He was a signatory of the Treaty of Fort Stanwix (1784), although this treaty was never ratified by the Iroquois, and participated in later meetings with both presidents George Washington and Thomas Jefferson.
Split into simpler sentences: He was a signatory of the Treaty of Fort Stanwix (1784), although this treaty was never ratified by the Iroquois. He also participated in later meetings with both presidents George Washington and Thomas Jefferson.