St John's Gate, in Clerkenwell, Middlesex, now within central London, is one of the few tangible remains from Clerkenwell's monastic past. It was built in 1504 by Prior Thomas Docwra as the south entrance to the inner precinct of Clerkenwell Priory, the English headquarters of the Knights of the Order of St John (known as the Knights Hospitaller).
The Priory of St John was founded in the 1140s for the Knights Hospitaller, a monastic order dedicated both to caring for the sick and to military service in support of pilgrimages to Jerusalem.
Over centuries, St John’s Gate has served many functions, including as a coffee house run by the father of William Hogarth, a tavern known as the Old Jerusalem, and the headquarters for the revived Order of St John which created the St John Ambulance.