He died of old age, pretty much. He was an elderly man to begin with, and the stress and strain of defeating the Cybermen in 'The Tenth Planet' took its toll. He collapsed in the TARDIS and in a scene that no video footage remains for, he regenerates into the Second Doctor.
Time Lords regenerate because they have a injury or something is wrong, it's their way of healing themselves.
Trenzalore (his final resting place), in the town of Christmas
The eighth Doctor regenerated offscreen and nothing is known about how or why he regenerated. The eighth Doctor appeared onscreen only once in a TV movie. We know th Time War happened between the TV movie and the start of the 2005 series. It's widely assumed that whatever the Doctor did to end the Time War caused him to regenerate.
He regenerated because his current body was getting old, so it was of natural causes.
Yes. River Song regenerated twice - once as a child, and once as Amy's friend 'Mel'. When Mel was injured, she regenerated into the version of River Song we first saw in Silence in the Library. However she gave her remaining regenerations up to save the Doctor, meaning her death in Forest of the Dead was her last, though her mind lives on inside CAL.
He will regenerate into the 12th Doctor.
He'll regenerate into the 13th Doctor.
Eventually yes, he will regenerate into the twelfth Doctor.
The fourth Doctor fell off a bridge.
Romana was another Time Lord, like the Doctor.
Peter Davison.
In the movie, The End Of Time.
Time Lords regenerate because they have a injury or something is wrong, it's their way of healing themselves.
It is unknown, the Eighth Doctor only appeared in a movie.
He played the first Doctor back in 1963, he lasted 3 years on Dr who and his character had to regenerate after an attack from the cybermen.
the Cybermen, just like the Daleks both made their appearances with the first doctor from Doctor Who. William Hartnell played the first doctor and unlike the Daleks, the Cybermen were the first aliens/monsters who greatly hurt the doctor and made him have to regenerate into the 2 doctor, played by Patrick Troughton. The Cybermen wounded the Doctor on the story arc, "The Tenth Planet". It was the second story arc in the 4th season of the show.
Trenzalore (his final resting place), in the town of Christmas