During the colonial period, Guyana's economy was focused on plantation agriculture, which initially depended on slave labor. Guyana saw major slave rebellions in 1763 and again in 1823. Great Britain passed the Slavery Abolition Act in British Parliament that abolished slavery in most British colonies, freeing more than 800,000 enslaved Africans in the Caribbean and South Africa as well as a small number in Canada. It received Royal Assent on August 28, 1833, and took effect on August 1, 1834. Thus, in the immediate period following this historical law, slavery was ended in British Guiana. To address the labor shortage, plantations began to contract indentured workers mainly from India. Eventually, these Indians joined forces with the Afro-Guyanese descendants of slaves to demand equal rights in government and society, demands underscored by the 1905 Ruimveldt Riots. Eventually, after the second world war, the British Empire pursued policy decolonization of its overseas territories and independence was granted to British Guiana on May 26, 1966.