Early ages

Prehistory
Neolithic tools found in the Kathmandu Valley indicate that people have been living in the Himalayan region for at least 9,000 years. It appears that people who were probably of Kirant ethnicity lived in Nepal more than 2,500 years ago. The Kirant are a tribe of jungle and mountain people who migrated from various parts of India and the Himalayas.
[edit] Legends and Ancient times
Though very little or sporadic things are known about the early history of Nepal, Asia, legends and documented references, like the following, reach back to the first millennium BCE:
Also, the presence of historical sites, e.g., Valmiki ashram, indicates the presence of Sanatana (ancient) Hindu culture in Nepal at that period.
The epic Mahabharata mentions the Kiratas among the inhabitants of Nepal. Kirati king Yalambar had the dubious honor of being slain in the battle of the Mahabharata, in which gods and mortals fought alongside each other. Legend credits him with meeting Indra, the lord of heaven, who ventured into the Valley in human guise. It is said that during the battle of Mahabharata, Yalamber went to witness the battle with a view to take the side of the losing party. Lord Krishna, knowing the intention of Yalamber and the strength and unity of the Kiratas, thought that the war would unnecessarily be prolonged if Yalamber sided with the Kauravas. So, by a clever stroke of diplomacy, Lord Krishna cut off Yalamber's head.
According to some of the chronicles, the successors of Ne were the gopālavaṃśi or "Cowherd family", whose names often end in -gupta and are said to have ruled for some 491 years. They are said to have been followed by the mahaiṣapālavaṃśa or "Buffalo-herder Dynasty", established by an Indian Rajput named Bhul Singh.
inscriptions found on archeological stoneworks, which list mostly the dates and commissioners of these constructions, also communicate royal edicts, religious mantras or historical notes sometimes and, through the corroboration of local myths with such evidence, a people prior to the Licchavi have been identified, known as the Kirata.