Similarly in the USA the international slave trade was banned after 1808. And over a period of decades slavery was banned in the northern states(yes, slavery was legal everywhere in the USA, even New York in the early 19th century, but in the north was banned by the 1820's. It was not very common in the north though and gets little press today. The Missouri Compromise of 1820, the Wilmot Proviso of 1850 and the Dred Scott decision of 1857 swayed the legality of slavery in the non southern states back and forth. Similarly when Lincoln issued the Emancipation Proclamation in 1863, it only freed slaves in Confederate held portions of the south, not those in Maryland, Delaware, W. Virginia or other Union held areas. They were not freed until the passage of an amendment to the Constitution in 1865.
Ah the deep darker sides of history not oft discussed and now overlooked.
