request In hindsight, the most important attendees were the ambassadors sent by Byzantine emperor Alexius I Comnenus. Alexius had been excommunicated by Gregory VII, and been through a series of reinstatements in the Church, but Urban had ultimately lifted the excommunication when he became pope in 1088, and relations between the east and west were at least temporarily friendly. The Byzantine Empire had lost much of its territory in Asia Minor to the Seljuk Turks in the aftermath of the Battle of Manzikert in 1071, and Alexius hoped western knights could help him restore it. Upon hearing the Byzantine ambassadors' plea, Urban asked those present to lend aid to the Byzantine Emperor. However it is likely that Urban may have had some idea of an expedition to the East before Alexius's request, as Gregory VII had also called twice for one, but to no avail. Chronicler Most of the information about the Council of Piacenza comes from the chronicler Bernold of Constance, who may or may not have been present. No extant contemporary Byzantine sources felt the ambassadors were important enough to mention, although many Byzantine sources from this time no longer exist. For example, the council is mentioned by the 13th century chronicler Theodore Skoutariotes, who quotes now-lost contemporary works. References Piacenza Piacenza 1095 in Europe 11th century in Italy