During the 9th century CE, a number of sects arose that denied the existence of oral Torah. These sects came to be known as Karaites (literally, People of the Scripture), often referred to as Karaism, or Karaite Judaism, which distinguished them from the Rabbinates or Rabbinical Judaism.

Karaites used the lunar month and the solar year, but determined when to add a leap month by observing the barley crop, rather than a fixed calendar. This occasionally put their calendar month out of sync with traditional rabbinic Jews. Karaites began the first month with the first New Moon after the Vernal Equinox provided the barley was ready for harvest.

The biblical year began with the first New Moon after the barley in Israel reached the stage in ripeness called Abib. The period between one year and the next was either 12 or 13 lunar months. Because of this, Karaites checked the state of the Barley crop at the end of the 12th month. If the barley was Abib at this time, then the following New Moon was Hodesh Ha-Aviv (“New Moon of the Abib”). If the barley was still immature, the Karaites waited another month and then checked the barley again at the end of the 13th month.