Wearing turbans is common among Sikhs, including women, who refer to it as a Dastar. In certain other faith communities, the headgear also serves as a religious observance, including among Shia Muslims, who regard turban-wearing as Sunnah Mu'akkadah (confirmed tradition). Greeks, in ancient times, wore a distinctive style of turbans. Additionally, turbans have often been worn by nobility, regardless of religious background. They are also sometimes donned to protect hair or as a headwrap for women following cancer treatments.