Public Register of the Lyon Court. The last record in the Public Register of the Lyon Court for undifferenced Arms of Buchanan (i.e., the Chief's Arms) was recorded in 1675. Arms are meant to be rematriculated within a year and a day of succession; however, it is common practice that Arms be borne on apparency, that is without matriculating the Arms, for two or three generations, beyond this it may be difficult or impossible to demonstrate heirship. So while there may have been discussions and determinations within the Clan hierarchy regarding the Clan Chief, the claims of neither Buchanan of Auchmar (1723–1816) nor Buchanan-Hamilton (1828–1919) appear to have been ratified in a legal sense.