21 March 1915: birth of Ian Stuart Black, author of The Savages (1966), The War Machines (1966) and The Macra Terror (1967).
21 March 1923: birth of Peter Pratt, who played the Master in The Deadly Assassin (1976).
21 March 1936: birth of Roger Hammond, who played Francis Bacon in The Chase (1965) and Dr. Runciman in Mawdryn Undead (1983).
21 March 1946: birth of Timothy Dalton, who played Rassilon in The End of Time (2009-2010).
21 March 1983: birth of Bruno Langley, who played Adam in Dalek and The Long game (2005).
ii) broadcast anniversaries
21 March 1964: broadcast of "Rider from Shang-Tu", fifth episode of the story we now call Marco Polo. the Tardis crew are unable to persuade Marco polo that Tegana is the source of their problems, and he prevents their escape.
21 March 1970: broadcast of first episode of The Ambassadors of Death. An attempt to rescue a lost Mars probe is frustrated by a signal sent from a vacant warehouse; UNIT investigates and is attacked.
21 March 1981: broadcast of fourth episode of Logopolis, ending Season 18: last appearance of Tom Baker and first of Peter Davison as the Fourth Doctor regenerates into the Fifth, after falling from a radio telescope while preventing the Master from blackmailing the people of the Universe.
21 March 2009: broadcast of Fragments (Torchwood), the one with all the flashbacks.