In the late seventeenth and early eighteenth centuries, Baptists in middle colonies like Pennsylvania competed against a staggering variety of religious denominations and sects. Essential for establishing and maintaining their denomination in this context was the founding of the Philadelphia Baptist Association in 1707, the first Baptist institutional structure in America. In addition to tracing his family lineage, this chapter explores the early influences of the Philadelphia Baptist Association on Oliver Hart, along with the Baptist rituals and doctrines he absorbed in the Pennepek Baptist Church. Hart’s exposure to Quaker and Keithian antislavery sentiments in Pennsylvania is also considered.