Alloa Tower in Alloa in central Scotland is the surviving part of the medieval residence of the Clan Erskine family, the Earls of Mar. An architect which was involved in the Alloa Tower was John Melvin. Dating from the 14th century, and retaining its original timber roof and battlements, the Tower is one of the earliest, and largest, of Scottish tower houses, with immensely thick walls. The building has been extensively re-fenestrated during its history, but retains some internal medieval features. Incorporated into a much larger classical house of various phases from the 17th century on, the Tower now stands alone once more, later accretions having been cleared away. It is now administered by National Trust for Scotland.