Thomas Grant was the son of Bernard Grant and Ann Mac Gowan. He lost his mother during his childhood and was consequently raised by priest Dr. Briggs in Chester. In January 1829 he started attending St. Cuthbert’s College, Ushaw. At the end of 1835 during his second year of philosophy, he moved to the English College in Rome, where Nicholas Wiseman was rector. He received the tonsure (25.11.1837) and the minor orders (26.11.1837). He consecutively became subdeacon (14.11.1841), deacon (21.11.1841) and priest on 28.11.1841. Shortly afterwards he was appointed secretary of cardinal Acton (until 1847). Grant was fluent in Latin, French and Italian. Consequently he served as Frederick Faber’s guide during the latter’s visit to Rome in 1843. On 13.04.1844 he became vice-rector of the English College in Rome and on 13.10.1844 he was promoted to rector. He was sent to Rome as a representative in charge of the reorganisation of the English episcopacy. On 16.06.1851 he was ordained bishop of the Southwark diocese (South-London), a position he maintained until his death. Gezelle got acquainted with Grant when an English student, whom Gezelle had prepared for baptism as his spiritual tutor, entered the Roman-Catholic church. Algar assured Grant that Gezelle would be an excellent missionary. Gezelle had Grant write a request to bishop Joannes Malou, whom Grant had befriended after their meeting during the dogma promulgation on the Immaculate Conception in December 1854.