https://en.wikipedia.org/wiki/Visit_of_the_Marquis_de_Lafayette_to_the_United_States
http://rmc.library.cornell.edu/lafayette/exhibition/english/tour/
Lafayette. Words at the Tomb of Washington. [Mt. Vernon, October 17, 1824].
The feelings, which on this awful moment oppress my heart dont leave me the power of utterance. I can only thank you, my dear Custis for your precious gift and pray a silent homage to the tomb of the greatest and best of men, my paternal friend.
Lafayette thanks George Washington's adopted son, George Washington Parke Custis (1781-1857), for giving him a sprig of Cyprus plucked from the tomb of George Washington. An 1829 account by Auguste Levasseur, Lafayettes personal secretary, describes Lafayettes 1824 visit to Washingtons grave: the tomb is scarcely perceived amid the somber cypresses... Lafayette descended alone in the vault, and a few minutes thereafter reappeared, with his eyes overflowing with tears. He took his son and me by the hand, and led us into the tomb... We knelt reverentially near his coffin, which we respectfully saluted with our lips; rising, we mingled our tears with his.
They gave him a lock of hair from Washington that had been cut while he lie in state. He kept it with him until his riverboat hit a submerged log on the Mississippi at night. They had to leave the boat and were in the lifeboats when Lafayette remembered the box of hair was still in his room. He sent his assistant (read man servant) back to get it before the boat sank. He was successful.