Throughout his life, the third President of the United States, Thomas Jefferson, owned hundreds of African-American slaves, and his position on slavery has been studied and debated by his biographers and by scholars of slavery. Starting in 1767 at age 21, Jefferson inherited 5,000 acres of land and 52 slaves by his father's will. In 1768, Jefferson began construction of his Monticello plantation. Through his marriage to Martha Wayles in 1772 and inheritance from his father-in-law John Wayles, in 1773 Jefferson inherited two plantations and 135 slaves. By 1776, Jefferson was one of the largest planters in Virginia. However, the value of his property (land and slaves) was increasingly offset by his growing debts, which made it very difficult to free his slaves and thereby lose them as assets