The Carmen in victoriam Pisanorum ("Song on the occasion of the victory of the Pisans") is a poem celebrating the victory of the Italian maritime republics in the Mahdia campaign of 1087. It was probably written by a Pisan cleric within months of the campaign. G. H. Pertz was the first to note the historical value of the text in 1839. It is an important source for the development of Christian ideas about holy war on the eve of the First Crusade (1095–99), and may have been influenced by the contemporary theology of Anselm of Lucca and his circle. It seems to have influenced the "Gesta Francorum", an account of the First Crusade composed by someone in the south Italian contingent. All of the later Pisan sources for the Mahdia campaign rely mainly on it: the "Chronicon Pisanum" only adds details about the memorial church, the "Annales Pisani" of Bernardo Maragone only rewords the former, and the "Cronaca di Pisa" of Ranieri Sardo and the "Breviarium Pisanae historiae" add only legendary material to the account.