The encomienda was a disguised form of slavery practiced by the Spaniards in their colonies. It was the first of this type and it was used between the 16th and 17th centuries. This consisted in assigning a group of natives to 1 Spaniard. They would work for him and in return he would protect them and teach them religion. There were 2 types: the tribute and the personal services. Negative consequences: the indigenes were exploited, they lost their religion and they were discriminated. I think there were very few positive consequences. Maybe the main one is that when Dominican missionaries were able to see how cruel this process was, they not only abolished it, but discrimination was diminished in the colonies.