When the Metropolitan Museum bought this (in the late 1960s?), they paid the highest price that had ever been paid for a painting to that time. It was in private hands in England, and auctioned off. It is supposed to be in beautiful condition, much better than the Velasquezs in the Prado (which I have never seen). Apparently the former curator of the Prado used to clean the paintings by pressing squashed up pieces of bread on them. This did clean them, but it also flattened them, so the textural quality of those paintings has been lost.
It's amazing how great art is often damaged by caretakers. Who would have thought about using squashed up bread?