Hindus (Hindustani: [ndu] (listen), ) are persons who regard themselves as culturally, ethnically, or religiously adhering to aspects of Hinduism. Historically, the term has also been used as a geographical, cultural, and later religious identifier for people living in the Indian subcontinent. The historical meaning of the term Hindu has evolved with time. Starting with the Persian and Greek references to the land of the Indus in the 1st millennium BCE through the texts of the medieval era, the term Hindu implied a geographic, ethnic or cultural identifier for people living in the Indian subcontinent around or beyond the Sindhu (Indus) River. By the 16th century CE, the term began to refer to residents of the subcontinent who were not Turkic or Muslims. Hindoo is an archaic spelling variant, whose use today may be considered derogatory. The historical development of Hindu self-identity within the local Indian population, in a religious or cultural sense, is unclear. Competing theories state that Hindu identity developed in the British colonial era, or that it may have developed post-8th century CE after the Muslim invasions and medieval HinduMuslim wars. A sense of Hindu identity and the term Hindu appears in some texts dated between the 13th and 18th century in Sanskrit and Bengali. The 14th- and 18th-century Indian poets such as Vidyapati, Kabir and Eknath used the phrase Hindu dharma (Hinduism) and contrasted it with Turaka dharma (Islam). The Christian friar Sebastiao Manrique used the term 'Hindu' in a religious context in 1649. In the 18th century, European merchants and colonists began to refer to the followers of Indian religions collectively as Hindus, in contrast to Mohamedans for groups such as Turks, Mughals and Arabs, who were adherents of Islam.