The office of Lyon King of Arms dates from the 14th century. The earliest official record is of the appointment of a Lyon by King Robert the Bruce in 1318, but the office may be older. The position incorporates the ancient Celtic office of High Sennachie who was responsible for verifying the genealogy of the King of Scotland and for crowning the King at his coronation.
The Lord Lyon is the sole King of Arms in Scotland. He is Head of the Heraldic Executive and the Judge of the Court of the Lord Lyon which has jurisdiction over all heraldic business in Scotland.
He is assisted by Her Majesty's Officers of Arms, all of whom are members of the Royal Household. There are at present three senior Officers of Arms (Albany Herald, Rothesay Herald and Ross Herald) and two junior Officers of Arms (Carrick Pursuivant and Unicorn Pursuivant).
The Officers of Arms may be consulted on matters of heraldry and genealogy by members of the public and may represent their clients before the Lyon Court. The Officers of Arms also take part in ceremonial occasions.
An Act of the Scottish Parliament of 1592 gave the Lord Lyon responsibility for prosecuting as a criminal offence anyone who uses unauthorised Arms. The Court has its own Procurator Fiscal, an independent official prosecutor.
In 1672 a further Act of the Scottish Parliament authorised the creation of the Public Register of All Arms and Bearings in Scotland. This Register is maintained by the Lyon Clerk and Keeper of the Records and contains an official copy of every Coat of Arms granted in Scotland since 1672.