DOCTOR WHO: THE QUEST OF IMMORTALITY

Doctor who its an alien time wizard who save the day in the earth planet and live several adventures wth human companions, but each period of time he regenerate himself in other person.

The regeneration process its show in the program ( alongside a way to change the actor) as a type of immortality. The alien change his body but the memories are untouchable.

For the show the immortality its natural and its a way to show the advance of the future, the main character regenerate each time and each time and the adventures following.

The big bad foe its called the master and also have the power of regeneration, make the show an eternal fight of good vs evil.

This show began in 1963 and its one of the first to explore the concept of immortality, another scifi

As we can see the concept of immortality its very early in the television history, as a way to began the quest for an impossible dream.