The prince and president, surrounded by various dignitaries, may be the focus of this group portrait, but it's the image of George Washington that makes this painting especially interesting. His profile is outlined in the clouds (hint: look in the middle of painting, between the two groups of trees), as if implying the first president's presence at the joint British/American visit to his tomb.
The prince's visit to the Revolutionary War leader's grave in 1860 was celebrated as a sign of reconciliation between England and its former colonies. Author R. J. de Cordova also wrote about Washington's presence during the visit in his 1861 poem, "The Prince's Visit: A Humorous Description":
Now I'm not superstitious, have no faith in ghosts;
Don't believe in the rappings of angelic hosts;
But that WASHINGTON'S spirit was there to receive
This offering of peace, I am free to believe;
And I know, if it witnessed the scene by that grave,
That the soul of the great man forgot and forgave.
You can see the painting in person in our second-floor galleries. For a closer look at the nineteen-year-old Prince of Wales, take a look at the National Portrait Gallery's photograph of him that Rossiter used as the basis for the portrait.