Brennan's controversial actions and poor relations with clergy in both Dallas and St. John's led the Vatican to remove him from both posts and eventually place him in a monastery.
[4] After his father' death, Brennan immigrated to the United States with his mother and brothers, settling in Pennsylvania.
[6] While still in Austria, Brennan was ordained for the priesthood for the Diocese of Erie on July 4, 1880, by Johannes von Leiss [de], the Bishop of Brixen.
[3] Brennan was named a Chaplain of His Holiness with the title of monsignor by Pope Leo XIII on January 11, 1888.
[6] That same year, Bishop Tobias Mullen sent him to Rome as a delegate to Pope Leo's golden jubilee celebration of his priestly ordination.
[9] During his brief tenure, Brennan built 12 churches, increased the number of priests by thirteen, and saw the Catholic population rise from 15,000 to 20,000.
[6]The Texas Catholic was accused by Brennan's priests of being a publication "whose sole reason for existence seemed to be...to praise the bishop and his vicar general.
[9] In a letter pleading his cause to the Congregation for the Propagation of the Faith, he argued for Dallas' elevation over the predominantly Spanish-speaking Diocese of San Antonio by saying such a decision would lead to the "foreignization of the Southwest.
"[10] The El Paso Times ran an article on November 2, 1892, that falsely claimed Brennan had been appointed an archbishop.
[13] In December 1893, after the death of Bishop Thomas Joseph Power, Brennan falsely claimed to be administrator of the diocese.
[1] On October 7, 1905, he was officially relieved of his duties in Newfoundland and given the honorary title of titular bishop of Caesarea in Mauretania.