He undertook further studies at Sant'Isidoro a Capo le Case, Rome before teaching theology in Naples.

[4] Tyrrell was also appointed the vicar apostolic of the Diocese of Kilmore by Pope Innocent XI on either 9 February 1678[5] or 21 March 1678.

[2][6] Tyrrell was forced into hiding on the outbreak of the Popish Plot crisis in autumn 1678.

[1] Upon the accession of James II of England, Tyrrell travelled to London with Dominic Maguire to pledge loyalty to the new king.

[8][9] Tyrrell is reputed to have said mass with Jacobite soldiers on the morning of the Battle of the Boyne.