Holy Trinity was incorporated by Archbishop John Ireland in November 1917. However, it was not until June 1940 that the first resident pastor, Fr. J. F. Siegienski, was assigned. Holy Trinity was initially a Polish parish and the sacrament of reconciliation was given in Polish. The first Mass was held on June 30, 1940. The church building and the rectory were built by 1942 and the church was blessed by Archbishop John Murray in 1942. The new convent and school were constructed in 1954. The convent housed the Felician
Sisters from Chicago, who staffed the school until 1978. Lay teachers have staffed the school since then. In 1985, Presentation Sisters of the Blessed Virgin Mary joined the parish staff and remained until 2000. The convent (now known as the Parish Center) has been remodeled and now provides office space for the school and parish. St. Augustine Oratory St. Augustine was incorporated on June 11, 1896. On August 30, 1896, Archbishop Ireland dedicated the new church which stood on the southeast corner of Fourth
Avenue and Grand Avenue, where Greystone Apartment building now stands. After being remodeled, expanded and reinforced with brick, the parish met with great tragedy. On March 31, 1923, St. Augustine burned to the ground. It was Holy Saturday, so Easter Masses were held at the Ideal Theater that year. Doing their best to replicate structures of the old church wherever possible, builders were
able to construct the current church structure for a Christmas Day 1924 opening. St. Augustine church was formally designated as an Oratory April 24, 2023, on the Feast of the Conversion of St. Augustine.