In Scotland the first king to use a numeral was Robert II who, in a preamble of a statute dated 1371-72, is described as Secundus. The original does not exist but there is a contemporary text in The Black Book. He was also so described on 4 April 1373 in the Declaration of the Succession to the Scottish Throne, of which the original document survives. James IV introduced his numbering on coins, and James VI on Royal seals. 

There was some difficulty with numbering when the thrones of England and Scotland were united in 1603. As this union did not unite the parliaments, which event did not take place until 1707, the Stuart kings continued the use of individual numbers for each country, such as James VI and VII in Scotland and James I and II in England. William III appeared as William II on the Scottish Royal seals. When Edward VII came to the throne a petition was sent from Scotland, which resulted in their letter boxes bearing ER instead of EVIIR.

When the late Queen succeeded there was more intense feeling in Scotland on the matter, and it was announced that any subsequent sovereign whose number was different in England and Scotland would take the higher number, eg if we had another King James he would be known as James VIII instead of James III, while a King Alexander would be styled Alexander IV although there have been no previous English Kings of that name. The letter boxes in Scotland in the reign of Elizabeth II only bear a representation of the Scottish crown without any initials or numbers. 

Image, top: Detail of portrait of Family of Henry VIII, c, 1545, unknown artist