Complex sentence: After revolutionary forces opposed to Díaz defeated the Federal Army, the revolutionaries and the Díaz regime negotiated regime change in the May 21,1911 Treaty of Ciudad Juárez.
Split into simpler sentences: After revolutionary forces opposed to Díaz defeated the Federal Army, the revolutionaries and the Díaz regime negotiated regime change. Negotiations culminated in the May 21,1911 Treaty of Ciudad Juárez.