St Thomas's Hospital has its origins in a small infirmary attached to the Augustinian Priory of St Mary the Virgin (St Mary Overie), which was destroyed by fire in 1212. The infirmary assumed the name of St Thomas the Martyr shortly after his canonization in 1173. After its destruction by fire the hospital was re-endowed by Peter de Rupibus, Bishop of Winchester, as a separate foundation independent of the Priory and administered by its own Master. It was built at the south end of London Bridge on a site occupied by the hospital from 1215 to 1862. In the early fifteenth century a new ward of eight beds was paid for by the Lord Mayor, Richard ('Dick') Whittington.
During the Reformation in 1540 the hospital, along with many other religious foundations, was dispossessed of its revenues and closed. The abolition of the religious houses deprived the poor of their chief source of relief, and the citizens of London presented a petition to Henry VIII. The King died before his intention to restore the hospital was carried out, and it was his son Edward VI who restored St Thomas's estates and revenues. The hospital re-opened with 120 beds and three Barber Surgeons, assisted by apprentices, were appointed, possibly marking the beginning of St Thomas's Hospital Medical School. A royal charter of 1553 made the Mayor and Commonalty and Citizens of London perpetual Governors of King's Hospital, as it was known for a time before becoming St Thomas's Hospital.
The hospital underwent an extensive building programme between 1693 and 1709, and about 300 beds were provided. Medical education was also formalised at this time, with regulations introduced to control the entry of pupils into the hospital. Students were educated on the wards long before this time. A record of one of the apprentices of a surgeon at St Thomas's appears in 1561. By the second half of the seventeenth century surgeons at the hospital were accepting the apprentices of other surgeons for short periods of tuition within the hospital. These students were the forerunners of dressers, and problems with their discipline and uncertainty over their status led to the formulation of some basic regulations to control the entry of students into the hospital. Surgeons were restricted to taking three dressers each, but this was frequently broken, and the number increased to four. The physicians at the hospital had some pupils, though a fewer number than the surgeons. From about the early 18th century the Hospital Apothecary also apprenticed pupils. Guy's Hospital opened in the grounds of St Thomas's in 1725, and lectures, wards and operations were attended by the students of both hospitals. In 1768 the arrangement was formalised and continued until Guy's established its own medical school in 1825.
Until the mid nineteenth century there were three types of student attending the medical school, the surgeons' apprentices and dressers, dressers who had served an apprenticeship elsewhere and completing their training with a particular surgeon, and pupils, who were not attached to any particular surgeon. Pupils first appeared in 1723, and tended to be on the periphery of surgical procedures. Their numbers were unrestricted and they paid smaller fees than dressers. All students were able to attend the courses of lectures provided by the teaching staff at the hospitals and dissection classes. The study of anatomy was the most prestigious course offered at St Thomas's. William Cheseldon, one of the most important and influential anatomists of the eighteenth century, was surgeon to St Thomas's Hospital from 1719 to 1738 and gave lectures from 1714. Other influential medical teachers included George Fordyce, who was Physician from 1770 to 1802, Henry Cline, Surgeon, from 1784 to 1812 and Sir Astley Paston Cooper, lecturer from 1797 to 1825. New accommodation for dissection classes was provided in 1814, and allowed up two hundred students at a time to practice dissection. Other courses offered to students after the unification of the medical schools included chemistry, materia medica, physiology and midwifery. A broadly based syllabus of medical lectures was delivered by William Saunders, Physician at Guy's Hospital, from about 1770. Students were also able to attend courses offered by the recognised private schools of medicine, notably the Windmill Street school, run by Samuel Sharp and later William and John Hunter, Joshua Brookes' Theatre of Anatomy in Blenheim Street and the Webb Street School of Anatomy and Medicine.
The popularity and influence of the medical schools led to the building of new facilities at St Thomas's Hospital. New accommodation was opened in 1814, and comprised a museum, laboratory, library, dissection room and large lecture theatre. A dispute over the appointment of the successor to the Surgeon Astley Cooper led to Guy's Hospital establishing its own medical school in 1825. St Thomas's lost several lecturers, and the popularity of Astley Cooper at Guy's and the establishment of new teaching hospitals in London such as King's College led to a period of decline for St Thomas's medical school. The school continued to offer lectures on a wide variety of subjects and provide regular clinical training, but falling student rolls and therefore income from fees hampered long term development and planning. After 1825 students of surgeons continued to attend operations at both hospitals, until a disagreement amongst the students in 1836 sparked off a riot in the operating theatre at St Thomas's and the arrangement ended. In 1842 the Hospital Governors stepped in to rationalise and improve the status of the medical school, and took over the management for the next sixteen years. A medical school fund was established and administered by the Hospital Treasurer to pay for the general running costs of the school, including the salaries of the non-teaching staff. A Medical School Committee was created to govern the school, appoint lecturers and oversee expenditure. The first Dean, Dr Henry Burton, was appointed in 1849. In 1858, management of the school was restored to the physicians and surgeons and in 1860 to the teaching staff, as the school had become self-financing.
In 1866 the extension of the railway from London Bridge to Charing Cross forced the Hospital to move to a temporary site at Newington. A site at Stangate in Lambeth, at the foot of Westminster Bridge, was bought from the Metropolitan Board of Works for ?95,000. Queen Victoria laid the foundation stone of the new building in 1868, which was also opened by her in 1871. The new building was designed by Henry Currey to take 588 beds. The plan was supported by Florence Nightingale, who had chosen St Thomas's as the hospital in which to found her training school for nurses. The new accommodation and new teaching staff, including Charles Murchison, Physician to the hospital from 1871 to 1879, heralded a good start for the new medical school. However, by 1892 most of the teaching staff had left and the new student intake was only forty-three. The enlargement of facilities at the school helped revive the school's reputation, and by 1900 student numbers were improving and increased rapidly.
St Thomas's Hospital and Medical School were seriously disrupted by the second world war. The hospital's status as a casualty clearance station, with sixteen wards closed and a limited out-patients' service meant that clinical teaching was impossible. Students were dispersed among other London hospitals and the pre-clinical school went to Wadham College, Cambridge. By March 1940 the anticipated aerial bombing had not taken place, and the medical school had reformed, the out-patients' service resumed and 250 civilian beds opened at Lambeth. However bombing raids in the Autumn severely damaged the hospital. Arrangements were made to move staff and patients to a hutted hospital at Hydestile, near Godalming, which had previously been occupied by Australian troops. By 1943 St Thomas's Hospital comprised 184 beds at the London site, 334 in Hydesville and 50 maternity beds in Woking. By the end of the war four ward buildings, three operating theatres, most accommodation for nurses and a large section of the out-patients department had been destroyed.
With the establishment of the National Health Service the medical school became a separate corporate body in 1948 and one of the general medical schools of the University of London. In 1949 the school accepted its first female medical student. The annual intake of students continued to increase throughout the 1960s and 1970s. Since the end of the second world war to the 1970s there has been almost continuous redevelopment of the site. In 1982 the medical schools of Guy's and St Thomas's Hospitals reunited as the United Medical and Dental Schools of Guy's and St Thomas' Hospitals (UMDS). The new institution was then enlarged by the amalgamation of the Royal Dental Hospital of London School of Dental Surgery with Guy's Dental School on 1 August 1983 and the addition on the Institute of Dermatology on 1 August 1985. In 1990 King's College London began discussions with the United Schools and, following formal agreement to merge in 1992 and the King's College London Act 1997, the formal merger with UMDS took place on 1 August 1998. The merger created three new schools: the Guy's, King's and St Thomas' Schools of Medicine, of Dentistry and of Biomedical Sciences, and reconfigured part of the former School of Life, Basic Medical & Health Sciences as the new School of Health & Life Sciences.