Kishimoto borrows heavily from both Japanese mythology (Jiayra/Tsuande/Orochimaru - Frog/Slug/Snake story) and Chinese Mythology (Hokage's monkey summon and the diamond pole are allusions to the chinese classic "Journey to the West").Originally posted by: -Sharingan-Kakashi-
I found this searching in google for Jiraiya, I guess it is the story of Jiraiya, Tsunade, and Orochimaru in Japanese mythology. Check it out http://www.kiseido.com/printss/ji.html