Carnival in the Caribbean has a complicated birthright, tied as it is to colonialism, religious conversion, and ultimately freedom and celebration. The festival originated with Italian Catholics in Europe, later spreading to the French and Spanish, who brought the pre-Lenten tradition when they settled (and brought slaves to) Trinidad, Dominica, Haiti, Martinique, and other islands.
The word Carnival itself is thought to mean "farewell to meat" or "farewell to flesh," the former referencing the Catholic practice of abstaining from red meat from Ash Wednesday until Easter. The latter explanation, while possibly apocryphal, is said to be emblematic of the sensuous abandon that came to define the Caribbean celebration of the holiday.
Historians believe the first "modern" Caribbean Carnival to have originated in Trinidad and Tobago in the late 18th century, as a flood of French emigres brought the Masquerade tradition with them to the island, although Fat Tuesday celebrations were almost certainly taking place at least a century before that.
By the beginning of the 18th century there were already a large number of free blacks in Trinidad mixed with French immigrants, earlier Spanish settlers, and British nationals (the island came under British control in 1797). This allowed for Carnival to transform from an implanted European celebration to a more heterogenous cultural froth. With the end of slavery in 1834, the now completely free populace could outwardly celebrate their native culture and their emancipation through dress, music, and dancing.
From Trinidad and Tobago, Carnival spread to many other islands, where the tradition fused with unique local cultures – salsa showcases on Antigua, for instance, and calypso in Dominica. Some celebrations have moved off the Easter calendar and are celebrated in the late spring or summer.
If you want to plan a trip to Carnival, the original destination, Trinidad, is the still the biggest and wildest party, but there are many other islands where you can experience Carnival -- almost year-round!