In 1278 the Co-Principality of Andorra was established by a treaty called the Pareage. It was ruled by the French head of State, and the Spanish Bishop of Urgell. In 1993 the system of government was modified to provide for a parliamentary democracy with the former rulers as titular heads of State.
     In 1978 the French postal service issued the stamp picturing the Preamble to the Treaty of 1278 to mark the 700th anniversary of the Co-Principality.