Originally, the Signet was the private seal of the early Kings of Scots, and the Writers to the Signet were those authorised to supervise its use and, later, to act as clerks to the Courts. The earliest recorded use of the Signet was in 1369, and Writers to the Signet were included as members of the College of Justice when it was established in 1532, but the Society did not take definite shape until 1594, when the King's Secretary, as Keeper of the Signet, granted Commissions to a Deputy Keeper and eighteen other writers.
The function of the Society has changed much since then, but every summons initiating an action in the Court of Session still "passes the Signet", meaning that it is stamped with the Signet. It gives the pursuer authority on behalf of the Queen to serve the writ on the defender. There used to be a Signet Office, which was next to, but separate from, the Court of Session, and was administered by two members of the Society of Writers to the Signet. In 1976 the Signet Office was merged with the General Department of the Court of Session. The present Signet was made by the Royal Mint in 1954.
The Keeper of the Signet is a Scottish office, now combined with that of Lord Clerk Register. The Lord Clerk Register grants a commission to the Principal Clerk of Session to allow the Signet to be used.
The Lord Clerk Register, in his capacity as Keeper of the Signet, also fulfils a ceremonial function as the senior officer of the Society of Writers to the Signet. The Lord Clerk Register issues commissions to new members. Although the Society is a private body, the Register of Commissions forms part of the records of the Court of Session, held by the National Archives of Scotland.