1187 - Retroactive Effects
Retroactive - Goes back in the beginning.
GR: No retroactive effect on fruits & interest. Only the principal has a retroactive effect.
EFF: Creditor/Buyer becomes the owner, retroactively making them owner since at the start of the obligation.
Ex. A promised B dog on May 1. Accepted Dog on December 30. RA = B is owner since May 1.