Most Holy Trinity parish was founded as the German Church of the Holy Trinity in 1841. It was the first National parish in the Brooklyn diocese, and officially the first Catholic parish in Williamsburgh (Sts. Peter and Paul began services in 1840, but was not formally established until 1844). Most Holy Trinity was also the mother church for a host of other German parishes over time. Holy Trinity was founded by Father John Raffeiner, a wealthy doctor-turned-priest from Austria.