The Pennsylvania Hospital was originally conceived in 1751 by Dr. Thomas Bond as an institution "for the reception and cure of the sick poor ... free of charge" and was funded grace to donations of the people of Philadelphia.

On September 2, 1751, Mathias Koplin donated the first plot of ground for the new hospital.

The first (temporary) building was opened on February 6, 1752, on High Street (now Market Street). Elizabeth Gardner, a Quaker widow, was appointed Matron of the hospital.

As the hospital received support of the leading families in Philadelphia, its permanence was secured, and Samuel Rhoads had been appointed architect of the new building.

Thomas Stretch is among the leading citizens of Philadelphia and one of the founders of Pennsylvania Hospital.

He is a member of the Union Fire Company, also known as Benjamin Franklin's Bucket Brigade and a founder of the social club known as Schuylkill Fishing Company, and the Club’s first governor in 1732; he will be re-elected annually until his death in 1765.

Stretch is a director of the Philadelphia Contributionship (Hand-in-Hand fire mark) from 1758 to 1761.

In the Pennsylvania Gazette of May 29, 1755, Thomas Stretch appears as one of the largest subscribers (with Benjamin Franklin and others) to the fund for the Pennsylvania Hospital.

The Stretch family and Benjamin Franklin each provided half of the original capital to fund the hospital.