[LABEO libro sexto posteriorum epitomatorum a IAUOLENO.] §3.5.42.prCum pecuniam eius nomine solueres, qui tibi nihil mandauerat, negotiorum gestorum actio tibi competit, cum ea solutione debitor a creditore liberatus sit: nisi si quid debitoris interfuit eam pecuniam non solui.
[LABEO, Epitomes of Posterior Works, Book VI, by JAVOLENUS] When you have paid money on behalf of someone who had given you no mandate, an action on business transacted is available to you, since the debtor has been released from the creditor by that payment; unless it was of some concern to the debtor that that money should not be paid.