March 22:  U.S. Congress passes legislation prohibiting the manufacture, fitting, equipping, loading or dispatching of any vessel to be employed in the slave trade.

1795: Pinckney’s Treaty establishes commercial relations between U.S. and Spain.

1800: May 10:  U.S. enacts stiff penalties for American citizens serving voluntarily on slavers trading between two foreign countries.

1804: January 1:  The Republic of Haiti is proclaimed. The hemisphere’s second Republic is declared on January 1, 1804, by General Jean-Jacques Dessalines. Haiti, or Ayiti in Creole, is the name given to the land by the former Taino-Arawak peoples, meaning "mountainous country."

1807: British Parliament bans the Atlantic slave trade. Great Britain converts Sierra Leone into a crown colony.

1807: U.S. passes legislation banning slave trade, to take effect 1808.

1810: British negotiate an agreement with Portugal calling for gradual abolition of slave trade in the South Atlantic.

1815: At the Congress of Vienna, the British pressure Spain, Portugal, France and the Netherlands to agree to abolish the slave trade (though Spain and Portugal are permitted a few years of continued slaving to replenish labor supplies).

1817: September 23:  Great Britain and Spain sign a treaty prohibiting the slave trade: Spain agrees to end the slave trade north of the equator immediately, and south of the equator in 1820. British naval vessels are given right to search suspected slavers. Still, loopholes in the treaty undercut its goals. Slave trade flows strongly, 1815-1830. Slave economies of Cuba and Brazil expand rapidly. In the Le Louis case, British courts establish the principal that British naval vessels cannot search foreign vessels suspected of slaving unless permitted by their respective countries -- a ruling that hampers British efforts to suppress the slave trade.

1819: U.S. and Spain renew commercial agreements in the Adams-Onis Treaty. U.S. Congress passes legislation stiffening provisions against American participation in the slave trade. Britain stations a naval squadron on the West African coast to patrol against illegal slavers.

1820: May 15:  U.S. law makes slave trading piracy, punishable by the death penalty. The U.S. Navy dispatches four vessels to patrol the coast of West Africa for slavers. This initial campaign lasts only four years before the Americans recall the cruisers and break off cooperation with the British.

1824: Great Britain and the U.S. negotiate a treaty recognizing the slave trade as piracy and establishing procedures for joint suppression. But the Senate undercuts the treaty’s force in a series of amendments, and the British refuse to sign.

1825: The Antelope case: A U.S. Revenue Cutter seizes a slave ship, the Antelope, sailing under a Venezuelan flag with a cargo of 281 Africans. The U.S. Supreme Court hears the case and issues a unanimous opinion declaring the slave trade to be a violation of natural law, meaning it can be upheld only by positive law. But the ruling sets only some of the Africans free, holding that the U.S. could not prescribe law for other nations and noting that the slave trade was legal as far as Spain, Portugal, Venezuela were concerned. So the vessel is restored to its owners, along with those Africans designated by the court as Spanish property (numbering 39). A large-scale slave revolt breaks out in Jamaica -- brutally repressed.

1833: Great Britain passes the Abolition of Slavery Act, providing for emancipation in the British West Indies -- set to take effect August 1834. (Following emancipation, a 6-year period of apprenticeship is permitted.)

1835: June 28:  The Anglo-Spanish agreement on the slave trade is renewed, and enforcement is tightened. British cruisers are authorized to arrest suspected Spanish slavers and bring them before mixed commissions established at Sierra Leone and Havana. Vessels carrying specified "equipment articles" (extra mess gear, lumber, foodstuffs) are declared prima-facie to be slavers.

1837: Britain invites the U.S. and France to create an international patrol to interdict slaving. The U.S. declines to participate.

1838: In the British West Indies, most colonial assemblies have introduced legislation dismantling apprenticeships. Laws against vagrancy and squatting attempt to keep the social and labor system of the plantation economy intact, with varying results.

1839: January:  Nicholas Trist, U.S. Consul in Havana, recommends that the administration dispatch a naval squadron to West Africa to patrol for slavers, warning that the British would police American vessels if the U.S. did not.

June 12:  The British navy brig Buzzard escorts two American slavers, the brig Eagle and the schooner Clara, to New York City to be tried as pirates. Two more arrive several weeks later, and another pair later that fall. The Amistad is seized off Long Island and taken to New London. (Fall) U.S. federal officers arrest several vessel owners in Baltimore implicated by the British as slave traders. Several schooners being built for the trade are seized as well. Turner’s The Slave Ship (also known as Slavers Throwing Overboard the Dead and Dying -- Typhoon coming on) goes on display at the Royal Academy in London.

1841: Nicholas Trist is dismissed as U.S. Consul in Havana, amid allegations he connived at, or at any rate took no effort to suppress, frequent illegal sales of U.S. vessels to Spanish slave traders.

source: http://amistad.mysticseaport.org/timeline/atlantic.slave.trade.html