Before 1328, celebrations were held at irregular intervals, but at the guild of that year it was decreed that subsequent guilds should be held every 20 years. After this, there were breaks in the pattern for various reasons, but an unbroken series were held from 1542 to 1922. A full 400-year sequence was frustrated by the cancellation of the 1942 guild due to World War II, but the cycle resumed in 1952.