Ancyra was attacked without success by Abbasid forces in 776 and in 798/99. In 805, Emperor Nikephoros I (r. 802–811) strengthened its fortifications, a fact which probably saved it from sack during the large-scale invasion of Anatolia by Caliph Harun al-Rashid in the next year. Arab sources report that Harun and his successor al-Ma'mun (r. 813–833) took the city, but this information is later invention. In 838, however, during the Amorium campaign, the armies of Caliph al-Mu'tasim (r. 833–842) converged and met at the city; abandoned by its inhabitants, Ancara was razed to the ground, before the Arab armies went on to besiege and destroy Amorium. In 859, Emperor Michael III (r. 842–867) came to the city during a campaign against the Arabs, and ordered its fortifications restored. In 872, the city was menaced, but not taken, by the Paulicians under Chrysocheir. The last Arab raid to reach the city was undertaken in 931, by the Abbasid governor of Tarsus, Thamal al-Dulafi, but the city again was not captured. Early Christian martyrs of Ancyra, about whom little is known, included Proklos and Hilarios who were natives of the otherwise unknown nearby village of Kallippi, and suffered repression under the emperor Trajan (98–117). In the 280s we hear of Philumenos, a Christian corn merchant from southern Anatolia, being captured and martyred in Ankara, and Eustathius. As in other Roman towns, the reign of Diocletian marked the culmination of the persecution of the Christians. In 303, Ancyra was one of the towns where the co-Emperors Diocletian and his deputy Galerius launched their anti-Christian persecution. In Ancyra, their first target was the 38-year-old Bishop of the town, whose name was Clement. Clement's life describes how he was taken to Rome, then sent back, and forced to undergo many interrogations and hardship before he, and his brother, and various companions were put to death. The remains of the church of St. Clement can be found today in a building just off Işıklar Caddesi in the Ulus district.