Orange River Convention
Orange River Convention (also known as Bloemfontein Convention) is a decision by Oranje. It is possible to enact if one have researched state and Government, have 10 prestige and have a relation of at least 75 with United Kingdom. It also requires that Oranje does not own any provinces, that has a British core. British South Africa has British cores, so one cannot have annexed South Africa. It gives a +25 better relation with United Kingdom and outlaws slavery.
The decision does not really give enough credit to the actual Orange River Convention. The convention was actually United Kingdoms formal recognition of Oranjes independence and outlawing slavery was merely a part of the convention.