As early as the 18th century, travelers remarked on the variety of color and features seen in slaves in Virginia, as European ancestry was obvious. Light-skinned slaves, some of whom were descendants of masters and their sons, were sometimes given better treatment on plantations, with domestic jobs inside the master's house, including as companions or maids to his legal children. Some of them were educated, or at least allowed to learn to read. Occasionally the master may have arranged for an apprenticeship for a mixed-race son and freed him upon its completion, especially in the first two decades after the American Revolution, when numerous slaves were freed in the Upper South. In this region, from the Revolution to 1810, the percentage of people of color who were free increased from 1 to more than 10 percent. By 1810, 75% of blacks in Delaware were free.