Later, nuts or coins imprinted with the god Janus became more common New Year's gifts. In the Middle Ages, Christians changed New Year's Day to December 25, the birth of Jesus. Then they changed it to March 25, a holiday called the Annunciation. In the sixteenth century, Pope Gregory XIII revised the Julian calendar, and the celebration of the new year was returned to January 1. The Julian and Gregorian calendars are solar calendars.
Some cultures have lunar calendars, however.
A year in a lunar calendar is less than 365 days because the months are based on the phases of the moon. The Chinese use a lunar calendar. The Chinese celebrate the holiday by exchanging gifts, having parades, and exploding firecrackers. One of twelve animals, such as a tiger, a rooster, or a dog, is associated with each new year. The Jewish New Year, Rosh Hashanah, is celebrated on the first two days of the Jewish calendar's first month, Tishri, which falls in September or October.