(text taken from Wikipedia (https://en.wikipedia.org/wiki/Gray%27s_Inn) on 19th September 2017)
The Honourable Society of Gray's Inn, commonly known as Gray's Inn, is one of the four Inns of Court (professional associations for barristers and judges) in London. To be called to the bar and practise as a barrister in England and Wales, an individual must belong to one of these Inns. Located at the intersection of High Holburn and Gray’s Inn Road, the Inn is both a professional body and a provider of office accommodation (chambers) for many barristers. The Inn is known for its gardens, or Walks, which have existed since at least 1597.
The early records of all four Inns of Court have been lost, and it is not known precisely when each was founded. The records of Gray's Inn itself are lost up until 1569, and the precise date of founding cannot therefore be verified. Lincoln’s Inn has the earliest surviving records. Gray's Inn dates from at least 1370 and takes its name from Baron Grey de Wilton, as the Inn was originally Wilton's family townhouse (or inn) within the Manor of Portpoole. A lease was taken for various parts of the inn by practising lawyers as both residential and working accommodation, and their apprentices were housed with them. From this the tradition of dining in "commons", probably by using the inn's main hall, followed as the most convenient arrangement for the members. Outside records from 1437 show that Gray's Inn was occupied by socii, or members of a society, at that date.
In 1456 Reginald de Gray, the owner of the Manor itself, sold the land to a group including Thomas Bryan. A few months later, the other members signed deeds of release, granting the property solely to Thomas Bryan. Bryan acted as either a feoffee or an owner representing the governing body of the Inn (there are some records suggesting he may have been a Bencher at this point) but in 1493 he transferred the ownership by charter to a group including Sir Robert Brudenell and Thomas Wodeward, reverting the ownership of the Inn partially back to the Gray family.
In 1506 the Inn was sold by the Gray family to Hugh Denys and a group of his feoffees including Roger Lupton. This was not a purchase on behalf of the society and after a five-year delay, it was transferred under the will of Denys in 1516 to the Carthusian House of Jesus of Bethlehem (Sheen Priory). which remained the Society's landlord until 1539, when the Second Act of Dissolution led to the Dissolution of the Monasteries and passed ownership of the Inn to the Crown.