If something happens very infrequently you may here it referred to as being ‘once in a blue moon’. In Lancashire, ‘appen tha’ll say ‘once in a Preston Guild’. The Preston Guild is celebrated enough to become part of the language but celebrated so infrequently to become a byword for rare events.
So what is the Preston Guild? And why is celebrated only once every twenty years?
The Preston Guild dates back to 1179 and is the only such ceremony still celebrated in the UK. In 1179, Henry II granted Preston the right to have a Guild Merchant. The Guild controlled the town’s craftsmen, the right to trade in the town and the town’s marketplace. Membership of the Guild was for life, and the membership rolls were updated infrequently.