Complex sentence: Since the late 1420s, Jonah had been living in the Simonov Monastery in Mosocw and was close to Metropolitan Photius, who make him Bishop of Ryazan and Murom.
Split into simpler sentences: Since the late 1420s, Jonah had been living in the Simonov Monastery. He was close to Metropolitan Photius, who would make him Bishop of Ryazan and Murom.