The alcabala (or alcavala) was a 10% sales tax traditionally levied in Castile, Spain. The members of the clergy and many towns were exempted from the tax, and nobles sometimes collected the tax for themselves instead of passing it on to the crown.
In The Colonies
In order to increase American revenue, the viceroy of New Granada gave instructions to remove the alcabala sales tax and the brandy monopoly from private tax-farmers. They acted without direct orders from Spain, and instead gave the royal officials the rights to the tax. The Alcabala sales tax was a trigger for the Quito Revolt in 1765. 1