1855 – Born on October 6th at Bally Cullen, Tipperary, Ireland. The first bishop of the Catholic Diocese of Dallas.
1863 – His family immigrated to the United States.
– Brennan began his studies for the priesthood at St. Bonaventure’s in Allegheny, New York.
1876 – Went to the University of Rouen, France and, from there, to the University of Innsbruck in Austria, where he was awarded a doctor of divinity degree.
1880 – He was ordained a priest on July 4th, in Brixen, Austria, by the local bishop, John de Leiss.
1891 – Brennan was named the first bishop of Dallas, and on April 5th, Tobias Mullen, bishop of Erie, consecrated him to the episcopacy.
– At age thirty-five, Brennan was the youngest Catholic bishop in the United States at the time.
1892 – Bishop Brennan was relieved of his Dallas post and transferred to St. John’s, Newfoundland, where he spent several years.
1904 – He went to Rome, where he retired to the monastery of Grottoferrata and remained until his death
1916 – Died on March 20th.