JOHN XVI  ., pope or antipope from 997 to 998, was a Calabrian Greek by birth, and a favourite of the empress Theophano, from whom he had received the bishopric of Placentia . His original name was Philagathus . In 995 he was sent by Otto III. on an embassy to Constantinople to negotiate a marriage with a Greek princess . On his way back he either accidentally or at the special request of Crescentius visited Rome . A little before this Gregory V., at the end of 996, had been compelled to flee from the city; and the wily and ambitious Greek had now no scruple in accepting the papal tiara from the hands of Crescentius . The arrival of Otto at Rome in the spring of 998 put a sudden end to the teacherous compact . John sought safety in flight, but was discovered in his place of hiding and brought back to Rome, where after enduring cruel and ignominious tortures he was immured in a dungeon .