During the glorious pontificate of Pope Jon XXIII, the Most Reverend Mariano S. Garriga, Bishop of Corpus Christi, called on the Missionaries of the Holy Family to be in Charge of the newly established parish of the Assumption of the Blessed Virgin Mary, Harlingen, Texas.
The Assumption Church used to be a mission chapel attended by the Oblates of the Immaculate Heart of Mary Church, who since 1849 have kept alive the faith among the Spanish-speakers along the Rio Grande from Brownsville to Laredo.
The first part of this odd looking church was built in 1910 and other parts were added in the course of time. It was the first Catholic church in downtown and was moved to this location in 1949. It is a frame building and has a seating capacity of 300 persons. Its parishioners were of the low-income class, having come in from farms and other smaller towns of the Rio Grande Valley and of Mexico to work in the various industries and businesses in Harlingen.
On December 15, 1958, Father Clemente Grzenia, M.S.F. was sent to this parish as its first pastor. There was no rectory. On January 2, 1959, the padres started taking up the census of the parish. After nine months of steady knocking at the doors this was the result: 831 Catholic families or 4578 souls; 586 living around the Assumption Church and 245 beyond the Arroyo Colorado and 157 fallen away or 800 souls lost to the Faith due to ignorance of religion or due to financial help of non-catholic religions.