Sion College, in London, is an institution founded by Royal Charter in 1630 as a college, guild of parochial clergy and almshouse, under the 1623 will of Thomas White, vicar of St Dunstan's in the West.
The clergy who benefit by the foundation are the incumbents of the City parishes, of parishes which adjoined the city bounds when the college was founded, and of parishes subsequently formed out of these.
The original buildings in London Wall were on a site previously occupied by Elsing Spital, a hospital for the blind founded in 1329, and earlier still by a nunnery. They comprised the almshouses, a hall and chapel, and the library added to the foundation by Dr John Simson, rector of St Olave Hart Street, one of White's executors. There were also, at least originally, apartments for students. The site was bounded by London Wall, Philip Lane, and Gayspur Lane (now Aldermanbury), roughly where Aldermanbury Square now stands. The first Court (committee) from 1630 consisted of John Gifford (President), Thomas Worrall and John Simson (Deans), and Francis Dee, Cornelius Burges, Edward Abbott and Thomas Wood (Assistants).
In the 1640s Sion College was regarded as a stronghold of the London presbyterians, their "de facto headquarters", and it took on a collective role from around 1645. The administration of the College fell into the hands of the parliamentarian side during 1643, as John Sedgwick of St Alphage London Wall took on the royalists President James Marsh, archdeacon of Chichester, and Edward Sparke. A work from 1646 by Anthony Burges claimed support from College members including the President Arthur Jackson, There were attacks on the College by the Independents John Goodwin (Sion-Colledg visited and Neophytopresbyteros) and John Price (1625?–1691) (The Pulpit Incendiary, 1648), and it was defended by Cornelius Burges (Sion College what it is, and doeth, 1648). William Jenkyn also attacked Goodwin (The Busie Bishop, or the Visitor Visited, and The Blind Guide, or Doling Doctor, 1648).