Dashavatara refers to the ten principal Avatars. In Vaishnava philosophy, an Avatar most commonly refers to the 'descent' and dasa refers to 'ten' in number. The ten most famous incarnations of Vishnu or sometimes Krishna are collectively known as the Dashavatara. This list is included in the Garuda Purana (1.86.10-11) and denotes those avatars most prominent in terms of their influence on human society.
Rama, Ramachandra, the prince and king of Ayodhya, appeared in the Treta Yuga. Rama is one of the most commonly adored gods in Hinduism and is known as an ideal man and hero of the epic Ramayana. Rama defeated and killed the king of Lanka, Ravana for capturing and imprisoning his wife Sita in the Ashoka Vatika in Lanka.