Ten actors who have played Time Lords on Doctor Who:
- Maurice Denham (Azmael a.k.a. Professor Edgeworth, "The Twin Dilemma"
- Bernard Horsfall (Chancellor Goth, "The Deadly Assassin")
- Denis Carey (Professor Chronotis, "Shada")
- Kate O'Mara (The Rani, first appearance "The Mark of the Rani")
- Patrick Troughton (The Doctor, first appearance "The Tenth Planet")
- John Arnatt (Borusa, "The Invasion of Time")
- Stephen Thome (Omega, "The Three Doctors")
- Michael Gough (Chancellor Hedin, "Arc of Infinity")
- Edward Brayshaw (The War Chief, "The War Games")
- Dinah Sheridan (Chancellor Flavia, "The Five Doctors")
Coincidence alert! I was inspired to do this list by seeing that today is the birthday of screenwriter Alfred Gough. That reminded me of the actor Michael Gough, who I remembered as having played the title role in the First Doctor serial "The Celestial Toymaker." I had completely forgotten that he had also appeared in a much later episode as a Time Lord -- until I selected Chancellor Hedin at random from a list of Time Lords on Wikipedia. How about that!