Without Northrop Mall, the University of Minnesota’s East Bank campus would be a mess. A city without a Main Street, a holiday table without a centerpiece. The campus sprawls in all directions without any unified architectural style.

This isn’t bad, and in one sense it’s an advantage: In a downtown setting, different styles still live cheek by jowl, one facade butting up against another, and the buildings are more facade than substance. In the pastoral setting of a campus, the buildings are placed like art objects in a gallery. You can walk all the way around, study them as discrete structures, not something plugged into a slot on a crowded street.

The mall, however, makes the charming buildings of the old campus look like toys scattered on the floor. It is the center of the campus — even though it’s not the center of campus life. It is the great public face of a great public institution. It is a manifestation of the historical metamorphosis that took the style of an illiberal empire built on conquest and slavery, and turned its architectural components into something that said Truth, Knowledge and Wisdom. Of all the places in the Twin Cities, it’s the one where the ancient Romans would have felt at home.

The mall was designed by Cass Gilbert in 1908, the renowned classical architect whose hand shaped the city’s great institutions. He’d already done the St. Paul Capitol Mall, a space whose breadth tends to make its power dissipate. The mall was smaller, and the identical buildings built in the ’20s — designed by the state’s official architect, Clarence Johnston, after Gilbert’s suggestions — define the space much better.

The buildings have a musical arrangement: the great sustained chord of Northrop, the quarter-notes of the thin buildings on its flank, Morrill and Johnston; the one-two-three-four count of the identical broad buildings that occupy most of the terrain, each with their own colonnades to echo the Northrop facade. (Walter Library is the best of the lot, with an interior that goes full Renaissance.) Two more thin buildings — Kolthoff and Ford — provide grace-note endings, then it all ends with the finale of Coffman, an updated version of Northrop that stares across the mall like a young man facing off his forebears. If it had been built all at once, it’s hard to see how they would have done it differently.

But it wasn’t, and here we learn how lucky we got. Most of the mall follows the same style: Renaissance Roman, a comfortably institutional style for banks and colleges and other places that wanted you to think Permanence and Gravity. They originally were supposed to be clad in stone, but thrifty regents opted for brick. It’s a reverse of Emperor Augustus’ remarks about Rome — he said he found a city of brick, and left it a city of stone. Well, brick will do nicely. Ivy helps.

Kolthoff and Ford, the buildings along Washington Avenue, came later. The architects were either under orders to conform, or had the sense to know that any addition to the mall must belong, not set itself apart. Newcomers had to complement the collection, or they’d look like some gate-crasher who heckles a solemn speech. (But enough about the Weisman.) Ford Hall strips down the classical vocabulary to square columns without capitals or pediment, something you’d get if you put a gun to the head of a 1950s architect, said, “Make with the Roman stuff, bub.” It’s an undistinguished building, but it fits and doesn’t embarrass itself. It belongs, and there are worse things you can say.

The worst of the lot is Kolthoff, which has all the sins of the ’70s: that blank brick goiter of an auditorium hanging over the sidewalk is hideous. The front looks like Mussolini’s tomb. As with Ford, the columns don’t even pretend to have any structural function. They’re tacked onto an empty facade that says, “Scurry in, Student No. 03634, and absorb science.” It’s the ultimate slag on the decorative classicism of the rest of the mall.

But it fits. It may be the last expenditure of the mall’s inheritance, but it fits.

As for Coffman, well, Gilbert would have frowned. It wasn’t supposed to be like this. The mall was supposed to march over Washington and continue down to the river with switchback pathways. It would have been glorious: fountains, bowers of trees and flowers. When you realize this was the plan, Coffman can look like a troll in the middle of the bridge, keeping you from crossing to the other side. Cutting off access to the river makes you want to pull your hair out, wondering what they were thinking; it’s like plopping a Kmart in the middle of Nicollet and Lake.

But it fits, too. You can read the 20th century by looking at Northrop and Coffman — rivals who work together. Northrop is the last breath of the past; Coffman’s stripped-down Moderne style is the confident newcomer squaring its shoulders to try a new approach. It’s the Old World speaking to the New, the imported traditions of Old Europe facing the crisp and confident lines of the American future.

You might guess that 30 years separated their construction. It was 12.

By the way: Clarence Johnston designed most of the mall, including Northrop. His son, also an architect, designed Coffman.

Today we build public spaces that want to suggest a different ideal. The natural ramble, an accommodation of the organic world. The mall is an imposition of order on nature, an assertion of rationality over feral spaces. It does not celebrate individuals, but doesn’t discourage them — it connects them to a cultural inheritance that gave rise, however tortuous the path, to the ideas of liberty and free inquiry. When you walk up to the steps of Northrop, you can well imagine a Roman senator standing on the steps and making a demand. You can also imagine a Cato or a Cicero crossing the stone plaza to argue the other side.

You can know nothing of history, and this space will still speak to you. Even if only in echoes.