Since 1650 (when the colony was founded) Suriname has had plantations as its most important means of incom. Especially the sugar plantations needed much labour for which slaves were used. The slaves were imported from West Africa, either directly or via the islands. When the country was taken from the British in 1667 there were about 1700 slaves and 400 whites, twenty years later there were 4000 slaves and 800 whites: in 1738 there were about 50.000 slaves and 2000 whites, and 400 plantations. Even under British rule slaves, Negroes as well as Amerindians (who were also used as slaves until 1683), escaped from the plantations, and fled into the forest. At the time of the arrival of Governor Van Sommelsdijck in 1683 some hundred slaves had escaped. In 1690 their numbers were increased by a few hundred more as a result of a revolt on a Jewish plantation. In 1738 the number of runaway Negroes or Maroons was estimated to be 6000. Ten percent of the total amount of slaves had fled then. The number increased further to 7000 in 1863. Since the colonists were unable to keep the Negroes from running away, or to force them to return to the plantations, they decided to make peace with them. In the meantime two large groups had been formed: Saramaccan tribe on the Saramacca River and the upper Suriname River, and the Djuka tribe on the Djuka Creek, a tributary of the Marowijne River. The origin of the name Djuka is unknown. A legend says that the runaway slaves found at the creek. where they settled a Djuka bird which they knew from Africa. They first named the creek after this bird, and later successively their tribe, their language and their territory. The estimated number of the imported negroes from Africa was about 300.000 to 350.000. The abolition of slavery took place on July 1st 1863. The descendants of the runaway slaves are now called "Bushcreoles", and the descendants of the not runaway slaves are called "Citycreoles"