[2] José Ribeiro da Fonseca Figueiredo e Sousa left for Rome in 1712, as part of the extraordinary embassy of the Marquis of Fontes.

The reason for his sudden departure from the country is obscure, but it was apparently due to his having incurred in King John V's wrath after standing accused of having forged genealogical documents to attain the status of fidalgo — fleeing persecution, he sought refuge and took his first vows at the Franciscan Monastery of Varatojo, but was soon after ordered to leave due to the Franciscans' fear of retaliation.

[3] Once in Italy, he made solemn vows at the Convent of San Bernardino di Orte and made his religious profession and was received into the Franciscan Order in the Convent of Santa Maria in Ara Coeli in Rome, 8 December 1712, taking the name "José Maria da Fonseca e Évora".

In 1740 he founded the large library in the old convent of Ara Coeli (the Biblioteca Eborense), and under his direction and patronage, the Annales Minorum of Luke Wadding were published in Rome in seventeen volumes, between the years 1731 and 1741.

Fonseca several times declined the episcopal dignity (namely the bishoprics of Osimo, Tivoli, and Assisi[2][3]), but finally accepted (1741) the See of Porto, to which he was nominated by John V of Portugal.