 An inscription on the gatehouse records that "AL THIS WARKE EXCEP THE AULD TOWR WAS BEGUN BE WILLIAM FORBES 15 APRIL 1584 AND ENDIT BE HIM 20 OCTOBER 1589".The home of a "Renaissance man", Tolquhon was designed for show rather than defence, and was the work of the mason-architect Thomas Leper or Leiper.Leper's distinctive triple shot-holes flank the main entrance, and are also found at nearby Arnage Castle and Dean Castle in Ayrshire.