Lammas is/was also called "Gule", from the Latin "Sanctus Petrus ad vincula" (admittedly, quite a stretch), or "St. Peter in Chains," the feast day on August 1 commemorating the release of the Prince of the Apostles from prison. This feast is still celebrated on traditional calendars. The feast, coming as it does as the corn is ripening, led to the "Lammas" idea. One of Robert Burns's incomparable love songs begins:

It was all on a Lammas nicht, when corn riggs are bonnie.