In Castro's own words, he was a Marxist-Leninist 4 years before the attack on Moncada - cutting short the common criticism that he only became a Marxist after he met Che.

Just learned from a Cuban comrade on ProleWiki about this. I set out to translate the speech he linked me to, which you can find in the post URL. Will be updating Castro's page soon with this info, because I literally never heard of this before.