To be called to the Bar and practise as a barrister in England and Wales, an individual must belong to one of the four Inns, i.e.

the Honourable Society of Lincoln’s Inn,
the Honourable Society of Gray’s Inn and
the Honourable Society of the Inner Temple
the Middle Temple

The exact origins of any of the Inns of Court, are not fully known. There is a tradition that none of the Inns of Court claims to be any older than the others. For many centuries it had been the view, held with varying degrees of confidence, that the starting point of the Inns of Court was a writ of Edward I made on the advice of his Council in 1292. In 1285 the King went to France to attend to the affairs of his Duchy of Aquitaine; he stayed away for nearly 4 years and during that time many of his judicial and administrative Officers in England engaged in corruption. On his return the King set up a commission to inquire into the whole matter and many of the Judges were disgraced and dismissed. The extant records of Lincoln’s Inn open in 1422, the earliest of any of the Inns of Court; but a society of lawyers by that name was then already in existence. It is likely that it evolved during the late part of the fourteenth century. In contrast to many of the colleges of Oxford or Cambridge, which it resembles, there was no conscious founding or dated charter.

First, why “Inn”? As well as applying to the houses used by travellers and pilgrims - the usage that usually comes to mind - the term, or its Latin equivalent hospitium, also applied to the large houses of magnates of all kinds, such as statesmen, civil servants, and lawyers, whose business brought them to town, especially when Parliament and the courts were in session. This type of inn was often not simply an individual residence but provided accommodation for a whole retinue of guests, and typically included, both as a focus for medieval living arrangements and as a status symbol, a hall. In 1370 the Manor House is described for the first time as "hospitium" (a hostel). That change of description suggests a gathering of lodgers at the Manor House by 1370 and it seems probable that the "hospitium" was a learned society of lawyers, because only eighteen years later two members became Serjeants. In the year 1388 there is record of members of Gray's Inn, the Middle Temple and the Inner Temple graduating as Serjeants-at-law.

Law students, or “apprentices” of law, who at the period learnt their craft largely by attending court, sought shared accommodation during the legal terms, sometimes in part of an inn of a magnate who did not need it. Originally there were at least twenty inns associated with lawyers. Gradually they became places of legal education, and there emerged the four principal Inns of Court (i.e. Inns of the men of Court) that we know today.