The first mention of a school at St. Mary Parish (now Blessed Trinity Parish) was in 1913.  Economic conditions were a big factor in preventing a continuous fundraising program until 1946.  In 1938, the idea of a parish school again surfaced, but the aftermath of the Depression and financial insecurities prevented further development.

      In 1942, it was suggested that a multi-purpose center be built specifically for religious education classes, wedding receptions, funeral dinners, etc.  The archbishop, however, refused the concept and said that a proper school should be built instead.  In 1946 the parish voted to create a parochial school and approved construction.

      In 1948, work began on the Sisters’ house on Summer Street (currently this is part of the Religious Education Offices and Staff Lounge areas).  This was built, at a cost of $26,000, adjacent to where the new school building would soon be built.  Work on the new school building began October 21, 1949.

      The Most Reverend Moses E Kiley, Archbishop of Milwaukee, dedicated the new school November 1, 1951.

      The school building consisted of 8 modern classrooms, a combination auditorium / gymnasium, and library.  The gymnasium – auditorium is on the 3^rd floor.  The classrooms were opened to children on September 5^th of 1951.  The enrollment in grades 1 – 6 was 185, and in 2 years when they would have all eight grades they anticipated it to be at least 250.  The faculty was composed of the Sisters of St. Francis of Assisi.  Enrollment of the school peaked between 290 – 322 students from 1959 – 1967.

      In September 1968, St. Mary’s dropped the 7^th and 8^th grades as a result of a “growing scarcity of teaching nuns and rising financial costs.”  Enrollment that year was 223 students.  At this time a School Board was created to assist the principal and parish priest in running the school.  Two of the classrooms formerly used by 7^th and 8^th grade were used by the public school for 3^rd grade.

      In 1994, St. Mary’s embarked on an expansion project with the construction of a library.  This expansion was further improved upon with a $20,000 grant from the Archdiocese of Milwaukee in 1997 for a new computer lab in the new addition.  A Preschool and Kindergarten were also added that year.  Sister Marcia, principal at that time, was instrumental in getting this project completed.  In fact, the addition was dedicated to her for her 21 years of service to St. Mary School as principal.  Many, many students have been educated at St. Mary School under her leadership.  She retired in 1999.

      Currently there are no longer any Sisters teaching at the school.  It is taught by lay teachers.  In 2005 and 2006 respectively, St. Mary’s brought back the seventh and eighth grades to the school.  Besides the core subjects, St. Mary School now offers specialist classes such as Spanish, Technology, Music, and Art.