John XVI, born Johannes Philagathos, called by Latin chroniclers Piligato or Filagatto (died ca 1001) was an antipope from 997 to 998.
Born at Rossano in the Byzantine territories of Southern Italy, he was the chaplain of Theophanu, the Empress consort of Emperor Otto II (973–983), who had come from Constantinople. Twice he acted as Imperial chancellor in Italy for Otto II, in 980-982, whereupon he was appointed Abbot of Nonantola, and in 991-992. Between his sojourns in Italy he was appointed tutor to the seven-year-old Emperor's son, Otto III, in 987. By the Empress's persuasion he was appointed bishop of Piacenza, and he was sent to Constantinople to accompany home a Byzantine princess for the younger Otto. After the Emperor's death, the youthful Emperor Otto III (983–1002) came to the aid of Pope John XV (985–996) in 996, to put down the rebellion of a faction led by the rich and powerful Roman nobleman Crescentius the Younger. Otto III stopped to be acclaimed King of Lombardy at Pavia, and failed to reach Rome before the Pope died. Once in Rome, Otto III engineered the election of his cousin Bruno of Carinthia as Pope Gregory V (996–999), and the new pontiff then crowned Otto III Emperor, 21 May 996.
Once Otto III had returned to Germany, the faction headed by Crescentius II violently unseated Gregory V and, with the active support of the Eastern Emperor, Basil II, acclaimed John as Pope John XVI (997–998). A synod of the Western bishops held in 997 at the Imperial capital in Italy, Pavia, decided in Gregory V's favour and excommunicated John.
The revolt of Crescentius II was decisively suppressed by Otto III, who marched once again upon Rome, in February 998. John XVI fled, but the Emperor's troops pursued and captured him, cut off his nose and ears, cut out his tongue, broke his fingers and blinded him, that he might not write, and publicly degraded him before Otto III and Gregory V. At the intercession of Saint Nilus the Younger, one of his countrymen, his life was spared: he was sent to the monastery of Fulda, in Germany, where he died about 1001.
Johann's consent to be enthroned as pope against the claims of Gregory can be seen as a manipulation of the constant political struggles by the Roman nobles against Imperial power, accruing to the advantage of Byzantine influence against the widening of Imperial power in Rome, where Gregory was the first German pontiff.
Because he was not a legitimate pope, the next three Pope Johns, John XVII, John XVIII and John XIX, took the regnal numbers XVI, XVII and XVIII, but some historians of the Middle Ages corrected their names including Antipope Philagathos among the Popes, and the wrongly corrected sequencing was never subsequently corrected.