First Doctor

In the Unbound Universe, the First Doctor was the original of the Doctor.

Biography
The Doctor's original body, in this incarnation, the Doctor grew up with the Master and was friends with him while they were in school. One day, he stole a TARDIS and ran away. During his travels, his TARDIS got stuck in the shape of a police box. (AUDIO: Sympathy for the Devil)

Later on, he landed on Skaro and led the Great Siege, which led to their liberation from their Daleks. (AUDIO: Masters of War) At the end of his life, he regenerated into the Second Doctor. (AUDIO: Sympathy for the Devil)