Valmiki is celebrated as the harbinger-poet in Sanskrit literature. The epic Ramayana, dated variously from the 5th century BCE to first century BCE, is attributed to him, based on the attribution in the text itself. He is revered as Ādi Kavi, the first poet, author of Ramayana, the first epic poem.
The Ramayana, originally written by Valmiki, consists of 24,000 shlokas and seven cantos (kaṇḍas). The Ramayana is composed of about 480,002 words, being a quarter of the length of the full text of the Mahabharata or about four times the length of the Iliad. The Ramayana tells the story of a prince, Rama of the city of Ayodhya in the Kingdom of Kosala, whose wife Sita is abducted by Ravana, the demon-king (Asura) of Lanka. Valmiki's Ramayana is dated variously from 500 BCE to 100 BCE or about co-eval with early versions of the Mahabharata. As with many traditional epics, it has gone through a process of interpolations and redactions, making it impossible to date accurately.
British satirist Aubrey Menen says that Valmiki was "recognized as a literary genius," and thus was considered, "an outlaw," presumably because of his "philosophic scepticism," as part of an "Indian Enlightenment" period. Valmiki is also quoted as being the contemporary of Rama. Menen claims Valmiki is "the first author in all history to bring himself into his own composition."Wikipedia More info about author