Flemming states, [1]
The possession of Elphinston dates back to John Elphinston, who married Marjory Erth, heiress of Erthbeg, or Little Erth, and acquired with her the earliest possessions of the Elphinstons, which were the residences of the descendants of the main line for about a century and a half, and formed the nucleus of their estate. John died about 1340, and Alexander, before his succession, was one of eighty squires who garrisoned Stirling Castle when held by the English Warden, Sir Thomas Rokeby, in 1336.
[1] J. S. Fleming, Ancient Castles and Mansions of Stirling Nobility (Paisley: Alexander Gardner, 1902), 185, [HathiTrust].