I had the good fortune one summer to stay with my younger sister, who lived in Washington DC, a 10-minute subway ride to the National Gallery of Art. I visited almost every day that summer ! Andrea Del Castagno’s “David” (paint on leather - it’s a parade shield ! ) hanged there. It was ALWAYS a “landmark” for my journeys through the museum .. . THAT was 42 years ago !! I understand it is no longer on exhibit .. .