A thousand years ago it was the infirmary garden of the monastery, and it is said to be the oldest garden in England under continuous cultivation; the produce can have done little for the health of the monks, due to heavy lead pollution. (However, the monastery's kitchen garden was the Convent-Garden or Covent Garden, half a mile north). A special medicinal herbarium was completed in 1306.
Its current name refers to the Collegiate Church of St. Peter, Westminster Abbey, rather than to its component Westminster School of which Lord Burlington's College Dormitory building forms the west side. The north side is formed by the great hall of Westminster School (originally the monks' dormitory), and the houses of the Abbey canons; the east and south sides are a mediaeval wall with a watergate which formerly opened into the River Thames, now embanked fifty yards away beyond the House of Lords. Just outside the watergate, College Green is often seen in television interviews with politicians.