A Franciscan friar and author of a crusade treatise entitled Liber recuperationis Terre Sancte.
Fidenzio was born around 1230 in the area of Padua in northern Italy. By 1266 he was the vicar general of the Franciscan province of the Holy Land. After the conquest of the Templar fortress of Saphet in Galilee by the Mamlûks, he settled at Tripoli (mod. Trâblous, Lebanon). When news of the fall of Antioch (mod. Antakya, Turkey) reached him there in 1268, he dedicated himself to the rescue of Christian prisoners. In 1274, Fidenzio attended the Second Council of Lyons, where plans for a new crusade were discussed. Commissioned by Pope Gregory X to write a report on the reconquest of the Holy Land, Fidenzio returned to Tripoli. When the Mamlûks conquered the city in 1289, he again became active in the liberation of prisoners.
Fidenzio completed the Liber recuperationis Terre Sancte at the beginning of 1291 and presented it to Pope Nicholas IV. It is divided into two main parts. The first part is a his torical dissertation that, according to scholarly traditions prevailing at Acre (mod. ‘Akko, Israel), adopted a cyclical approach to history deriving from the seven days of Creation; six of these represented the periods of the past, while the seventh looked to the future, to say that the Holy Land would belong to the Christians. The account of the fifth period contains a critical analysis of the period of Frankish domination, insisting that by their faults, the Franks lost the Holy Land. One chapter is dedicated to an adverse biography of the prophet Muhammad, followed by descriptions of the vices of the Islamic faith and the Saracens. The second part of the treatise deals with the detail of the military campaign that would be required to reconquer the Holy Land. Fidenzio insisted on the meticulous preparation of an army and navy and on the need to raise a sufficient number of fighters, who had to be united under a perfect commander. In order to assure the success of the future crusade, Fidenzio emphasized the necessity of the spiritual training and moral behavior of the crusaders.