The present church building, a structure of exceptional beauty and harmony of form, was constructed in 1850. Its architect was Richard Upjohn, the foremost church architect of the mid-19th century. Its style is known as neo-gothic. It is the oldest church building in the City of Rome, and its greatest architectural treasure. The church was enlarged in 1866-1867 after the Civil War, and Upjohn’s son and grandson added the parish hall in 1885.