Jefferson's twilight years were spent, in part, defining and defending his legacy. During his final decade, Jefferson drafted an autobiography, created political memorandum books, became increasingly concerned about the preservation of historical documents, and staunchly defended his role as author of the Declaration of Independence. At key points in his life Jefferson had drawn up lists of his achievements, and on the verge of death he designed his own gravestone and epitaph: "Author of the Declaration of Independence [and] of the Statute of Virginia for religious freedom & Father of the University of Virginia." Though critics questioned his role in writing the Declaration of Independence and objected to his emerging role as a symbol of individual freedom, Jefferson insisted upon his authorship of the Declaration and reasserted his moral opposition to slavery. Nevertheless, Jefferson undoubtedly knew at his death on July 4, 1826, that the vagaries of life had left a vulnerable legacy. His slaves, land, and library would have to be sold to satisfy his creditors. Fear for his reputation and public legacy led him to beg his closest friend, James Madison, to “take care of me when dead.” In his final letter to Roger Weightman, Jefferson eloquently espoused the central role of the United States and the Declaration of Independence as signals of the blessings of self-government to the world.