Portugal is historically Britain's oldest ally, and with British support succeeded in having the re-incorporation of Olivença decreed in Article 105 of the Final Act, which stated that the Congress "understood the occupation of Olivença to be illegal and recognized Portugal's rights".
Portugal on ajalooliselt Suurbritannia vanim liitlane ja saavutas tema toetusega Olivenza taastamisnõude lisamise lõppakti artiklisse 105, mis väitis, et kongress "sai aru, et Olivenza okupeerimine on ebaseaduslik ja tunnustas Portugali õigusi".