The occasion was the 85th birthday of Tomas G. Masaryk, the first (and in 1935 still) President of Czechoslovakia. He was born on 3 March 1850, and the date in the cancellation is 3 March 1935, with his monogram TGM above the date. The coat of arms is the large coat of arms for Czechoslovakia (1918-39).
You can read more about him here:
http://en.wikipedia.org/wiki/Tom%C3...igue_Masaryk