The sermon dominated many protestant sects, so perhaps it's not surprising that the Greek revival style found greatest favor among the Protestant congregations while Catholics usually stayed with more rectangular forms.

At least one unusual religious building type can be a found throughout the Philadelphia region - the Quaker meeting house. Quaker meeting houses were often large open rooms frequently with galleries and fixed seating resembling the first wave of Congregationalist meeting houses in New England. Many Quaker meeting houses from the 18th century still exist in the greater Philadelphia region (although very few in the city itself), varying by size and complexity, but often showing consistency in an overall approach of design and execution. Meeting houses are often rather plain with a lack of ornate architectural detailing. They are sometimes square in plan, but more often rectangular and frequently oriented to a central point along one of the long sides of the building. Benches are arranged in a U formation around this focal point and multiple benches are placed at this focal point so that several members of the meeting can sit facing the rest of the members. This arrangement allows members to face each other rather than all face to a pulpit or alter, in keeping with the Quaker belief system of inner revelation rather than outer inspiration.
One of the founding principles of Pennsylvania was religious tolerance - the Quakers had been persecuted in England and they determined that all religions would be welcome in their holy experiment.

It's an irony that many places of worship in the oldest part of Philadelphia predate the remaining active Quaker meetinghouses in the area. Old Swedes Church, which is now Episcopalian, dates from the early 1700's and was originally built for the Swedes who settled in this area before William Penn. Other groups quickly established themselves, including Catholic, Presbyterian, Jewish, Methodist and Dutch Reformed. In an ecumenical musical chairs, many church buildings have changed religions over time with new congregations - in one particular case changing an Episcopal church, built in the Greek revival style, to a Greek Orthodox Church. Some church buildings have maintained their original appearance while others have been heavily modified such as St Paul's - a Georgian church transformed into a Greek revival building.

When looking at the trends of religious buildings in Philadelphia between the beginnings of the city till the 1850's, you can see certain cues to society as a whole. For example, two early Catholic churches, Old Saint Mary's from 1763 and Old Saint Joseph's from 1838, have very restrained exteriors without steeples or anything else to attract public attention. While the government in Pennsylvania freely allowed Catholics to practice, popular sentiment was not always supportive and Catholics had to keep a low profile in their architecture.

Another architectural trend that you can see playing out is the adoption of the Greek revival style to Christian churches. At first glance it seems t be a peculiar choice, given the western Christian traditional use of a plan based on the long rectangle of the of the Roman law court (basilica). However, Greek revival buildings sometimes had a floor plan approaching a square in proportion which put more of the congregation closer to the preacher and his sermon.
Religious Architecture