He defended the faith throughout his life, founding the Khalsa (a sect of sworn Sikh warriors) and introducing the five K’s that Sikhs must wear to this day, as well as naming the Sikh holy book the Guru Granth Sahib as his successor and eternal Guru. Processions are common when his birthday is celebrated, usually in January or December in the Gregorian calendar, featuring jubilant devotional songs, gatherings at Gurudwaras, and special meals and treats to share with each other.