3 March 1924: birth of John Woodnutt, who played George Hibbert in Spearhead from Space (1970), the Draconian Emperor in Frontier in Space (1973), Broton and the Duke of Forgill in Terror of the Zygons (1976), and Seron in The Keeper of Traken (1981).
3 March 2004: death of Sheila Dunn, who played Blossom Lefavre in The Daleks' Master Plan (First Doctor, 1965), the computer voice of the Electromatic company in The Invasion (Second Doctor, 1968), and Petra Williams in Inferno (Third Doctor, 1970). She was married to Douglas Camfield, who directed all three of those stories.
ii) broadcast anniversary
3 March 1973: broadcast of second episode of Frontier in Space. The Doctor and Jo are brought to Earth for questioning, where the Doctor is captured by the Draconians and then recaptured by the humans.
iii) date specified in canon
3 and 4 March 1215: setting of The King's Demons (1983).