The chief duties of the court are, firstly, the establishment of a person or organisation's right to bear arms or to claim a given pedigree, and secondly, the bringing of criminal prosecutions against those who use the arms of another without the right or permission to do so.
The Lord Lyon has jurisdiction only over Scotland, and appeals may be made from him to the highest Scottish court, the Court of Session, and then to the highest British court, the House of Lords.
The Lord Lyon has several English equivalents. While the Lord Lyon is the only "King of Arms," or a high heraldic officer, in Scotland, there are three English Kings of Arms: the Garter Principal King of Arms, the Clarenceaux King of Arms (responsible for southern England), and the Norroy and Ulster King of Arms (responsible for northern England and Northern Ireland). The Lord Lyon's Court, which is a heraldic authority responsible for granting arms, is paralleled in England by the College of Arms. Finally, as a judicial body, the Lord Lyon's Court is paralleled by the Court of Chivalry, and the Lord Lyon, as chief judge, by the Earl Marshal.