Agatho was a Sicilian, probably once a Benedictine (monks following the Rule of St. Benedict) monk at Palermo. There is good authority that he was over a hundred when he became pope in 678, succeeding Donus.

St Wilfrid of York, unjustly deposed by Theodore of Canterbury, came to Rome to appeal. Agatho held a synod at the Lateran that restored him to his see.

The main event of his reign was the Sixth Ecumenical Council at Constantinople in 680, where his legates presided. It practically ended the Monothelite (the claim that Christ had only a divine will, not also a human one) heresy. Agatho died before its decrees reached Rome. He was known for his kindness and charity and was called the Wonderworker for his many miracles. Both the Latin and Greek churches honour him.

Thin entry · the 1914 book gives only 220 words. We have not filled the gap with invented detail.

Agatho, a Sicilian by birth, was remarkable for his charity and gentleness.

​Agatho, Saint, Pope, b. towards the end of the sixth century in Sicily; d. in Rome, 681. It is generally believed that Agatho was originally a Benedictine [monks following the Rule of St. Benedict] monk at St. Hermes in Palermo, and there is good authority that he was more than 100 years old when, in 678, he ascended the papal chair as successor to Pope Donus. Shortly after Agatho became Pope, St. Wilfred, Archbishop of York, who had been unjustly and uncanonically deposed from his see by Theodore of Canterbury, arrived at Rome to invoke the authority of the Holy See in his behalf. At a synod which Pope Agatho convoked in the Lateran [St. John Lateran, the pope’s cathedral in Rome] to investigate the affair, Wilfred was restored to his see. The chief event of Agatho's pontificate is, however, the Sixth Œcumenical Council, held at Constantinople in 680, at which the papal legates presided and which practically ended the Monothelite heresy. Before the decrees of the council arrived in Rome for the approval of the pope, Agatho had died. He was buried in St. Peter's, 10 January, 681. Pope Agatho was remarkable for his affability and charity. On account of the many miracles he wrought he has been styled Thaumaturgus, or Wonderworker. His memory is celebrated by the Latin as well as the Greek church.

Mann, Lives of the Popes in the Early Middle Ages (London, 1902); Butler, Lives of the Saints (London, 1877); Montalembert, The Monks of the West (Boston), II, 383 sqq; Moberly in Dict. of Christ. Biogr. (London, 1877); Lobkowitz, Statistik der Pāpste (Freiburg and St. Louis, 1905).