Hindu law is a  code of laws applied to Hindus, Buddhists, Jains and Sikhs in British India. It is one of the oldest known  theories in the world .The term "Hindu law" is a colonial construction, and emerged after the colonial rule arrived in South Asia, and when in 1772 it was decided by British colonial officials, that European common law system would not be implemented in India, that Hindus of India would be ruled under their "Hindu law" and Muslims of India would be ruled under "Muslim law"  

modern Hindu law states:
1 The Hindu Marriage Act of 1955 goes in greater detail to define this legal Hindu, by stipulating in Section 2 that the Act applies:
(a) to any person who is a Hindu by religion in any of its forms and developments, including a Virashaiva, a Lingayat or a follower of the Brahmo, Prarthana or Arya Samaj,
(b) to any person who is a Buddhist, Jain or Sikh by religion, and
(c) to any other person domiciled in the territories to which this Act extends who is not a Muslim, Christian, Parsi or Jew by religion
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