Complex sentence: The Vail-Deane school, founded in 1869, boasted a rich history, and the school's Alumni Association was merged with the association in the 1990s, Wardlaw-Hartridge created a 6-8 Middle School on the Edison Campus.
Split into simpler sentences: The Vail-Deane school, founded in 1869, boasted a rich history, and the school's Alumni Association was merged with Wardlaw-Hartridge's. In the 1990s, Wardlaw-Hartridge created a 6-8 Middle School on the Edison Campus.