Coille-tor’, or ‘woodhill’, is the supposed derivation of the lands of Callender in Stirlingshire from which this family takes its name. The barony is believed to have been bestowed upon the first notable of this name around 1246. Nisbet relates the fascinating but unlikely story that the first of this name was a Roman from a fort near Ardoch, close to the modern town of Callender, and whose office it was to gather fuel for the fort – thus he was named ‘Calloner’, from the Latin, ‘calo’, meaning ‘log of wood’. Nisbet also states that the Callenders of that Ilk were clerks to the king; this could account for the billets which appear on the coat of arms and may represent sheets or scrolls of paper. Patrick Callender of that Ilk supported the cause of Edward Balliol, and his lands were forfeited by David II. The lands were granted to Sir William Livingstone by a charter dated 10 July 1347, and to secure his undisputed right to these lands he subsequently married Christian, the daughter and heiress of theforfeited Patrick. In 1641 Sir James Livingstone was raised to the peerage with the title Earl of Callender. Callender House is one of the largest stately homes in Scotland and is now in the care of the public authority. Hugh Callendar, a noted physicist, researched extensively in thermodynamics. He was Professor of Physics at the Royal College of Science in 1902. His son, G. S. Callendar, propounded the theory of climatic change brought about by industrial combustion, processes known as the Callendar effect, in 1938. His work is now used by scientists studying the greenhouse-effect theories of global warming.