[Sa'ar Chasm]

[color=#000000ost_uid0][quoteost_uid0]The part of the Doctor has changed hands several times. Three special episodes have featured multiple Doctors (the current occupant of the role plus some or all predecessors) interacting with each other.[/quoteost_uid0]

Wasn't the whole multiple-doctor thing caused by the fact that actors kept getting old and dying? I thought that when a Galifreyan dies, he (or she, I suppose) regenerates into a new form, and can do this 12 times.

The Doctor is dead, long live the Doctor.[/colorost_uid0]