One can probably say that Nepal is as old as the Himalayas, when a great lake filled the Kathmandu Valley. One legend holds that this lake was drained by a thunderbolt thrown against the walls of the Valley by the Hindu god Krishna. Another claims it was drained by the patriarch Manjushri as he wanted to get a closer look at a Swayambhu or Adhi-buddha, the beautiful lotus flower resting on the lake.
But the recorded history of Nepal does not start until around 800 BC, with the beginning of the Kirat Period. After that was the Lichhavi and Thakuri Period, followed by the Malla Period and finally the Shah Period.