On June 20, 1859 five men: H.Landsmann, W.Trampe, M.Koehler, H.Klages, and W. Lange met to form what was called "The First German Evangelical Lutheran Church of Carondelet". In 1872, when the current church was built, the name officially changed to "The Evangelical Lutheran St. Trinity Congregation U.A.C.". The name "St. Trinity" was the result of an error in translation of the Articles of Incorporation from German into English by Charles Frincke, Jr. The actual German name was "Heilige Dreieinigkeit", meaning Holy Trinity, or from the Latin, "Sanctus Trnitatus". The church building of 1872, designed by Rev. Stephan is still the current sanctuary used today. The cornerstone for the building was laid on September 27, 1872 and was dedicated June 29, 1873. The present Kilgen organ was installed in 1903.
Early in 1860, Otto Hanser was called to be the first pastor of the new congregation. Later that same year, George Steuber was called to be the first teacher for the school that was formed when the church first began.
Pastor Hanser served until the fall of 1862 when he took a call to Boston and the congregation called Rev. Hamann. He served until 1868 when poor health prompted him to ask for a leave of absence and the congregation called C.F.W. Sapper with the promise that he would become the pastor if Rev. Hamann could not continue his duties. Shortly thereafter, Rev. Hamann retired and Rev. Sapper served the congregation faithfully for the next 17 years.
On April 7, 1861 the congregation officially joined the church body that is now called The Lutheran Church-Missouri Synod.
In 1864 Teacher Steuber was succeeded by Teacher Kurz. After Teacher Kurz, there were numerous teachers each serving just a few years. During this time, however, the school grew and flourished so that a second classroom was added by converting a stable into a classroom and a second teacher was hired. The 1870's and 1880's were years of financial stress for the congregation. Much of that was due to the debt incurred with the building of new church buildings in 1872. There were also a number of special collections taken for various causes as well as for other Lutheran churches in the city of St. Louis.
In 1880 Teacher Pott was called and he served the school faithfully and well for over 20 years. This ended the succession of teacher changes. In 1883 Rev. Sapper took a call to Bloomington, IL and was succeeded by Rev. Achenbach.
By 1892, the school was becoming crowded with over 100 students and so a new school building was built along Vermont Ave. A youth group also begun that same year. During the 1890's the church gradually lowered its debt and by the end of the decade was in much better shape financially. In 1896 a third classroom and a third teacher was added.
In 1897, Rev Achenbach requested a leave of absence and the congregation called Rev. John Bernthal. St. Trinity called a seminary professor to serve as an assistant pastor and several professors assisted in this capacity for a number of years. One assistant pastor, Rev. Ruprecht, served as the first Sunday School superintendant which started in 1920.
In 1902 Teacher Pott retired after 20 years of service and again the school saw a number of teacher changes. Teacher George Hoerber arrives in 1905 and taught at St. Trinity for many years with several older members still remembering him for his strictness.
With the help of St. Trinity and its members, Gethsemane Lutheran Church in Lemay was formed in 1905.
On March 9, 1920, having served the congregation well over 23 years Rev Bernthal died. During his time he was regarded as a strong leader and the church experienced growth. Rev. Theodore Laetsch became St. Trinity's pastor and served until 1927 when he became a professor at Concordia Seminary. During Rev. Laetsch's pastorate, the congregation began holding two regular services on Sunday, the first in German and the second in English.
Rev. Emil Beckmann was installed as St. Trinity's pastor in December 3, 1929. Rev. Beckmann served until his resignation in April of 1954 for health reasons and Rev. Walter Ostermeier succeeded him.
After serving for 25 years, Teacher Hoerber resigned in 1930 and Teacher Grebring took over and taught along side Teacher Klawitter who had come to St. Trinity in 1926. In 1938 a kindergarten was added.
When Rev. Ostermeier took a call in 1958, Rev. John Fasholz was called to serve as an interim pastor. Rev. Fasholz served as pastor till 1965 when he took a call to teach at Lutheran High School South.
Rev. Edmund Lammert succeeded Rev. Fasholz and served as St. Trinity's sole pastor until his illness and death in 1986.
In 1969 St. Trinity's constitution was revised and women were given the right to vote at voters meetings. On December 15, 1969 seven ladies applied for voting membership. In 1988 the constitution was again revised and this time women were given the right to hold any office in the church.
At the close of the school year in 1976 school enrollment had dropped to 23 students from 161 in 1959. The congregation decided then to close the school after 116 years of ministry.
In September of 1986 St. Trinity installed it's tenth pastor, Rev. David Liebnau. In the 1990's three new outreach programs were started: a food pantry, Mission program in Africa, and a Parish Nurse ministry. Throughout the 1990's and 2000's St. Trinity saw a decline in membership, but has remained faithful to community outreach and Christian education.
With Rev. Liebnau retiring in October 2012, St. Trinity called interim Pastor James Rhiver..
Interim Pastor James Rhiver lead services until St. Trinity called its 11th Pastor, Rev. David Lewis. Pastor Lewis was installed on November 3, 2013 and began a new ministry within the Carondelet community.