In England, a thirteen lunar month calendar (lunar year) also known as a year and a day was still in use up to Tudor times. Robert Graves writes in the introductions to Greek Myths:

Time was first reckoned by lunations, and every important ceremony took place at a certain phase of the moon; the solstices and equinoxes not being exactly determined but approximated to the nearest new or full moon.... Even when, after careful astronomical observation, the solar year proved to have 364 days, with a few hours left over, it had to be divided into months—that is, moon-cycles—rather than into fractions of the solar cycle. These months later became what the english-speaking world still calls "common-law months," each of twenty-eight days … and, since the 364-day year is exactly divisible by twenty-eight, the annual sequence of popular festivals could be geared to these common-law months. As a religious tradition, the thirteen-month years survived among European peasants for more than a millennium after the adoption of the Julian Calendar [in 45 BCE]; thus Robin Hood, who lived at the time of Edward II [1284–1327] could exclaim in a ballad celebrating the May Day Festival:

How many merry months be in the year?

There are thirteen, I say ...

which a Tudor [1485–1603] editor has altered to "...There are but twelve, I say...." Thirteen, the number of the sun's death-month, has never lost its evil reputation among the superstitious.