During the 9th century C.E., 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, and they were distinguished 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.