Complex sentence: Zenkō-ji was founded before Buddhism in Japan was split into several different sects, so it currently belongs to both the Tendai and Jōdoshū schools of Buddhism, and is co-managed by twenty-five priests from the former school, and fourteen from the latter.
Split into simpler sentences: Zenkō-ji was founded before Buddhism in Japan split into several different sects. It currently belongs to both the Tendai and Jōdoshū schools of Buddhism, and is co-managed by twenty-five priests from the former school, and fourteen from the latter.