It can be established that closes existed on this site as early as 1520 by tracing the close names and the ownership of tenements ; tenements being tracts of land rather than large houses*.
A simplified diagram shows the layout of the 4 closes. This is a clickable map
The main conclusion which can be drawn from the length and spacing of the closes is that Mary King's Close was the most important thoroughfare of the four closes. It may have been the only one of the four which stretched all the way from the High Street to the Nor'Loch. The evidence on this point is slightly ambiguous. On the 1582 Ordnance Survey map there is no trace of Stewart's and Pearson's Close to the north of the City Chambers and in the case of Pearson's Close, the existing fine of the Close does seem to tail-off into an early wall. However, evidence is provided by the 1635 Tax Extant Roll that the number of tenants on Stewart's or Pearson's Close is similar to the number of tenants on one side of Mary King's Close. Mary King's Close was undoubtedly distinguished from the other three closes by having front access to properties on both sides. It was customary for houses to have their front entrances facing the close to their right (in this case to the east). Thus the doorways in Pearson's Close have front entrances on the west side of the passage and back entrance to properties in Allan's Close on the east side of the passage. The different types of entrance can be clearly seen in Pearson's Close where properties to the west (front entrance) have dressed lintels (or worked stone) and jambs and properties to the east (back entrances) have rubblestone arched entrance with rough lathe and plaster panels overhead. Similarly Stewart's Close had front entrances on its west side. However between Stewart's Close and Mary King's Close, there was space for two tenements with properties back-to-back. The 1635 Tax Roll confirms that there were properties on either side of Mary King's Close which 'belonged' to that Close.
The house on Mary King's Close has several features which date if at around 1750: the curved walls at either side of the front door; the door itself and the windows above it; the astragals on the windows north of the door and a number of mouldings in the hall. One of the most interesting finds in the house was a section of wall which was papered. It has been suggested that the wall paper was sent to the Victoria and Albert Museum for examination, where it was dated between 1714 and 1725. This apparent contradiction could be explained by the location of the wallpaper within a lavatory closet, where it is likely older paper would have been used.
One feature of most of the remains is the proliferation of vaulted rooms. This leads to the suspicion that where walls can be traced back to circa 1650, the ceilings are likely to be more recent and designed tu support the construction of the Royal Exchange.
*Extract from An Architectural Survey undertaken by Melanie Morris in March 1986, postgraduate student in Architectural Conservation at Heriot-Watt University.