Shudra is the fourth Varna, as prescribed in the Purusha Sukta of the Rig veda, which constitutes society into four varnas or Chaturvarna. The other three varnas are Brahmins (priests); Kshatriya (those with governing functions), and Vaishya (agriculturalists, cattle rearers and traders). According to this ancient text, the Shudra perform functions of serving the other three varna. The varna system became rigid in the later Vedic period. In modern Indian society, the government is taking steps to end the differences between various castes.