If I say, "Washington Crossing the Delaware," in your mind's eye you probably see it right away: the commanding general erect in a small boat on a wintry day, being rowed across the icy river to victory by a startlingly handsome crew. The flag is furled against the wind, in the background war horses are rearing. The general seems to have boat, river, weather and the future republic all under his command.

Last week I got a look at the 12-foot, 5-inch by 21-foot, 3-inch original, which fills an entire gallery wall in the Metropolitan Museum of Art in New York City. Its frame, not always shown in pictures of the painting, shimmers in gold leaf with shields mounted at the corners, adding to the distinctly Roman impression of the general's cloak and trappings.

Nothing about the image is incidental. It is all artistically designed for a purpose, although the scene is such an American icon that we tend to take it as simply true. And it is truth, although not literally. Washington would not have crossed the Delaware standing with one bent knee in such a small craft. Anybody who has ever tried to stand up in a pitching rowboat knows that pose would have led to "Washington Falls into the Delaware." The artist, Emanuel Leutze, set out to portray a godlike figure worthy to be called the Father of His Country and to inspire lasting confidence among the citizens. As, we know, he succeeded.

As we also know, that is not the whole story of George Washington. He was exactly the leader the would-be country needed, and he possessed a natural nobility in real life. He also owned slaves. He was imperfect, but he rejected all attempts to make him king.

The Met owns and exhibits many works of art done to portray the breathtaking beauty of this land and the character of its post-colonial men. And there are later visions: 19th-century scenes conveying the so-called "manifest destiny" of expansion to the frontiers. We are meant to understand that America the beautiful is also America the great.

Meanwhile, other things were happening to other Americans, and other artists were capturing them. As it proudly celebrates its 150th birthday this year, the Met has done some soul-searching and admitted humility about the lopsided way its collections have told Americans their story. The Hudson River School landscape artists, for example, sometimes added details showing what they took to be the demise of the Native American tribes — and a signal to white settlers and entrepreneurs to move in. Those paintings of limitless possibility for European Americans are contemporary with inhumane maltreatment of native peoples.

As an acknowledgment of both sides of that story, some Met works now come with an extra text label. Alongside the curatorial description of painting and painter is a statement about the scene from a Native American viewpoint. The added labels do not diminish the glory in the paintings; they add the depth of other emotions — loss, empathy, irony — and awareness that there is more to the story.

Likewise, sculptures and ceramics by indigenous and enslaved artists are now sharing galleries with well-established masterworks. Artworks from the Spanish-speaking Americas are appearing in the generally North American exhibitions. Artists contemporary with the recognized master painters and sculptors had a vision of their own. For decades, the museum and its visitors gave little thought to that.

The Metropolitan became one of the world's great art museums almost as soon as it opened 150 years ago. By now it is an icon itself. Unlike its collections from the Vikings or the Pharaohs, however, its American collection comes from a great society that is still flourishing and still coming to understand its roots. The 150-year-old Met tells that story better and more completely than ever. You should see it.

Lisa McGinley is a member of The Day Editorial Board.