The relationship between George Washington and slavery was complex, contradictory and evolved over time. It operated on two levels: his personal position as a slaveowning Virginia planter and later farmer; and his public positions first as commander-in-chief of the Continental Army during the American Revolutionary War and later as President of the United States. He owned slaves almost his entire life, having inherited the first ten slaves at the age of eleven on the death of his father in 1743. In adulthood his personal slaveholding increased through inheritance, purchase and natural increase, and he gained control of dower slaves belonging to the Custis estate on his marriage in 1759 to Martha Dandridge Custis. He put his slaves to work on his Mount Vernon estate, which in time grew to some 8,000 acres (3,200 ha) encompassing five separate farms, initially planting tobacco but diversifying into grain crops in the mid 1760s. Washington's early attitudes to slavery reflected the prevailing Virginia planter views of the day; he demonstrated no moral qualms about the institution and referred to his slaves as "a Species of Property." He became skeptical about the economic efficacy of slavery before the American Revolution, and grew increasingly disillusioned with the institution after it. Washington remained dependent on slave labor, and by the time of his death in 1799 he owned 124 slaves, whom he freed in his will, and controlled another 193, most of whom remained enslaved.