Alhammarret's Archive

• WWizards of the Coast2015-06-22
  Official Ruling
  If two or more replacement effects would apply to a card-drawing event, the player drawing the card chooses the order in which to apply them.
• WWizards of the Coast2015-06-22
  Official Ruling
  If an effect would set your life total to a specific number that’s higher than your current life total, that effect would cause you to gain life equal to the difference. Alhammarret’s Archive will then double the amount of life that effect would cause you to gain. For example, if you have 3 life and an effect says that your life total “becomes 10,” your life total will actually become 17.
• WWizards of the Coast2015-06-22
  Official Ruling
  In a Two-Headed Giant game, only the controller of Alhammarret’s Archive is affected by it. If that player’s teammate gains life, Alhammarret’s Archive will have no effect, even when that life gain is applied to the team’s shared life total.
• WWizards of the Coast2015-06-22
  Official Ruling
  Similarly, the effects of the last abilities of multiple Archives are cumulative. If you control two, you’ll draw four times the number of cards, and so on.
• WWizards of the Coast2015-06-22
  Official Ruling
  Because Alhammarret’s Archive is legendary, it’s unlikely that one player will control two. However, if that happens, life gained by that player will be multiplied by four. Three Archives will multiply that life gain by eight, and so on.

Rulings via Scryfall