There is, however, no positive evidence of building before the seventeenth century. Until the 1530's the area was divided between various owners, mostly corporate, including the Abbey of Westminster, the Convent of Abingdon, and the Hospital of St. James, the last of which occupied, probably since the eleventh century, a position immediately adjacent, where St. James's Palace now stands. St. James's Fair, established in 1290 for the benefit of the hospital, was probably held nearby. Beyond this little is known of the medieval history of the area.

The new pattern east of St. James's Street formed a somewhat self-contained residential area, not communicating outward very readily. One of the first streets to be built was Jermyn Street and its long east-to-west line indicates the predominant axis of the area, towards St. James's Street rather than north-and-south. Its line was paralleled to the south by that of Charles Street and King Street through the square. But the easternmost and westernmost communication of the area was little more open than that northward and southward, probably in part because the frontages to the Haymarket and St. James's Street were already built upon. Instead, narrow foot-passages terminated the lines of Jermyn Street and Charles Street-King Street.

It is to be remarked that the more notable of the houses first erected on the land between Piccadilly and Jermyn Street faced the latter. The siting of St. James's Church did nothing to 'open' the area towards Piccadilly, as it was separated until the 1760's from that highway by a row of buildings. It was usually regarded as being in Jermyn Street, whence its principal entrance looked down to the square.

One of the most fashionable of London churches, St. James's was more closely connected with the wealthy area lying to its south than is evident nowadays. It attracted a metropolitan congregation, but the ceremony of its consecration from a house in the square does not altogether misrepresent its partial function as the 'chapel' of St. Albans's estate. In the design of its interior Wren achieved a notable triumph of intellect and sensibility, and its exterior was consonant with the sometimes deceptive plainness of the new streets to the south of it.

The old-established institutions of the area include White's and Boodle's, but it is significant that a number of the links with the eighteenth century are provided by continuity in some form of 'trade'-Fortnum and Mason's, Hatchard's, Lock's and Christie's may be mentioned, while the Cavendish Hotel dates from the late eighteenth century, and the Golden Lion public house in King Street can be traced back to at least 1732. Perhaps most notably, Berry Brothers and Rudd have links of family succession in trade on the same site back to about 1699, a longer continuity than is represented by any private family with a house in the area.

Proximity to the royal palace affected the character of the area from the start; lodgings were sought here by officers of the Court, as well as by grandees wanting a good address. From the first St. James's Square was attractive to the greatest names in the kingdom and St. Albans's own residence here set a prevailing tone. The official removal of the Court from Whitehall to St. James's Palace in 1698 nevertheless had some effect on the social character of the area.

A similar distinction characterized some of the places of public resort and recreation in eighteenth-century St. James's. The Opera House in the Haymarket, Almack's assembly rooms in King Street, and the Shakespeare Gallery in Pall Mall contained beauties of design or decoration comparable in brilliance and refinement to those of the finest private houses.