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drafted an autobiography, created political memorandum books, became increasingly concerned about the preservation of historical documents, and staunchly defended his role as author of the Declaration of Independence.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