Barts was founded in 1123 by Rahere (died 1144, and entombed in the nearby Priory Church of St Bartholomew the Great), a favourite courtier of King Henry I.

The dissolution of the monasteries did not affect the running of Barts as a hospital, but left it in a precarious position by removing its income.

[2] The hospital became legally styled as the "House of the Poore in Farringdon in the suburbs of the City of London of Henry VIII's Foundation", although the title was never used by the general public.

[2] St Bartholomew's Hospital has existed on the same site since its founding in the 12th century, surviving both the Great Fire of London and the Blitz.

Its museum, which is open Tuesdays to Fridays every week, shows how medical care has developed over this time and explains the history of the hospital.

The church has a 15th-century tower and vestry, and its connections with the hospital can be seen not only in its early-20th century stained glass window of a nurse, a gift from the Worshipful Company of Glaziers, but also in commemorative plaques adorning its interior.

Philip Hardwick, a Royal Academician, was also engaged in the rebuilding of the Church of St Bartholomew-the-Less in 1823 and donated the fountain in the hospital's courtyard.

The average income of the hospital was £40,000 (derived chiefly from rents and funded property) and the number of governors exceeded 300.

A minor injuries unit was established at Barts for small cases (which often represent a significant part of the workload of A&E services) but urgent and major work goes to other hospitals.

The plan came under threat when it was announced that the works would be procured under a private finance initiative contract; the Save Barts campaign continued to protest.

[22] Barts continues to be associated with excellence at its medical school's significant research and teaching facilities on the Charterhouse Square site.

[24] In 2018, Nuffield Health, a not-for-profit healthcare organisation, was granted planning permission to redevelop the former pathology and residential staff quarters building into a new private hospital.

[28][29] Both Schools have a strong and respected history dating back over 120 years and have produced many nurse leaders and educators.

[46] The collections are searchable on the Barts Health NHS Trust online catalogue, which contains information on over 50,000 entries and covering an 800-year span.

[50] A chemical laboratory at Barts was the location of the initial meeting of Sherlock Holmes and Dr. Watson in Arthur Conan Doyle's 1887 novel A Study in Scarlet.

This fictional connection led to a donation by the Tokyo "Sherlock Holmes Appreciation Society" to the Save Barts Campaign in the 1990s.

[54] Since 2022 Bedrock Radio (a registered charity)[55] broadcasts to St Bartholomew's Hospital and wider Barts Health Trust.