Generalísimo Máximo Gómez y Báez was the military commander in Cuba's War of Independence (1895-1898). I think this is (Scott #676) a 1961 re-issue of the 1954 portrait series. On the earlier stamp (Scott #520), instead of the question mark, there was the date "1833". His birth date was apparently wrong, contested, and is now generally agreed on to be 1836.
Due to the trade embargo on Cuba, imposed by President Kennedy in 1962, Cuban stamps were prohibited from importation. So, it has been rather difficult to evaluate stamps of Cuba issued after July of 1961. This was issue in August of 1961. It's really interesting to get to see one - Thanks!