Sorry, I think it as a more common word in portuguese than in english (maybe I mistranslated it too).
Maecenas would be someone that gives money to an artist be able to produce its art. Long time ago, before artists could access market to finance themselves, great artists (e.g. Renaissance artists) often needed a Maecenas to pay the bills while they were creating their masterpieces. No financial interests, arts for art sake (sure, other reasons like vanity, social influence, power demonstration and etc were involved too).
Not sure this was an accurate explanation, but I tried.
#4 is quite similar of what I have in mind. But no connotations of influence in theory - in practice, I imagine that was hard to have zero influence on the supported artist.
Maecenas would be someone that gives money to an artist be able to produce its art. Long time ago, before artists could access market to finance themselves, great artists (e.g. Renaissance artists) often needed a Maecenas to pay the bills while they were creating their masterpieces. No financial interests, arts for art sake (sure, other reasons like vanity, social influence, power demonstration and etc were involved too).
Not sure this was an accurate explanation, but I tried.