Due to an bizarre series of Masquerades, I start my turn owning exactly two cards, both of which are in my hand (so no Native Village mat, Tavern mat, Prince, etc., etc.). By the end of the turn I have gained a Province and I did not trash, return, or exchange any cards in the process. At no point in the game, this turn included, have I in any way interacted with any tokens (including placing or manipulating Adventures tokens, taking Pirate Ship tokens, placing or gaining Curses from Embargo tokens, or anything at all to do with VP/Coin/Debt tokens), though some or all of them may nonetheless be present in the Kingdom. No Attack cards from other players (e.g. Swamp Hag) had any effects on me this turn.
However, I also gained a second card besides the Province, and in fact, on account of which two cards were in my hand, I could not have fulfilled all the conditions in the last paragraph without also gaining that other card. What other card did I gain, and what two cards started the turn in my hand?