It was a lot later (1300s), but Ibn Battuta seems to have done just that. Guy leaves Morocco and just keeps going on and on, till he ends up in China. Though perhaps even more incredibly he actually does come all the way back. The historicity of his accounts is disputed and maybe only a part of it is true, but even if he only got as far as India, I still find it fascinating to imagine doing at that time.

There are viking inscriptions and stuff at the hagia sophia, that's a hell of an adventure for the time!