Quantum praedecessores is a papal bull issued on 1 December 1145 by Pope Eugenius III, calling for a Second Crusade.
[2] As with most papal bulls, it had no specific title, and has come to be known by its opening words; in Latin the first sentence read "Quantum praedecessores nostri Romani pontifices pro liberatione Orientalis Ecclesiae laboraverunt, antiquorum relatione didicimus, et in gestis eorum scriptum reperimus" – in English, "How much our predecessors the Roman pontiffs did labour for the deliverance of the oriental church, we have learned from the accounts of the ancients and have found it written in their acts.
"[3] The bull, issued at Vetralla, briefly recounted the acts of the First Crusade, and lamented the loss of Edessa, one of the oldest Christian cities.
The bull was addressed directly to Louis VII of France and his subjects, and promised the remission of sins for all those who took the cross, as well as ecclesiastical protection for their families and possessions, just as Pope Urban II had done before the First Crusade.
The First Crusade had no such bull – support was gathered at the Council of Clermont in 1095, and spread quickly through popular preaching.