THE OLDEN TIMES, they are a-changin'.

Last week, the dinner-theater chain Medieval Times, which specializes in meaty, sometimes cheesy "royal feasts," announced a 30th-anniversary upgrade: the addition of a vegan menu.

As wild as that is, it turns out this is just one of many history-based dinner providers, national and Philly-based, that are adding veggie menu options to their repertoire.

And not compromising on historical authenticity, either, in some cases.

At the best-known historical-immersion destination, Virginia's Colonial Williamsburg, menus have been "traditional" since the town was relaunched as a tourist destination in the early 1930s. But last year, one of the town's signature historical restaurants introduced a vegan burger to its dinner menu.

I wanted a firsthand look-see.

On a family vacation - and my first big road trip in a while - I was gratified to find that traveling vegan is getting easier. Let me give a shout-out to two prime examples: The Richmond, Va., veggie spot Fresca on Addison had great vegan sandwiches and desserts, and the irrepressible Bob Tubbs at The Cedars of Williamsburg had vegan pancakes and much more at the ready from the first breakfast.

The Williamsburg restaurant in question is Traditions, in the Lodge, where executive chef Rhys Lewis and chef Justin Addison developed the new burger, a blend of navy beans and black-eyed peas. With the usual fixin's but sandwiched between flat pitas, this is a concoction both singular and tasty, with a solid spice blend that gives the beans a kick.

Addison explained that the idea for the burger came while picking (historically correct) navy beans at a local farm. But this may be just the start - Addison looked forward to eventually doing "something different for vegans and vegetarians every day."

Colonial-era . . . tofu?

Meanwhile, back in Old City, historical mainstay City Tavern last year introduced fried tofu as an entrée, supplementing vegan appetizers and sides like potato leek soup and corn chowder.

Wait, tofu? In Colonial Philadelphia? It turns out Benjamin Franklin (who tried vegetarianism on more than one occasion) sent a 1770 letter to John Bartram including instructions for making an animal-free cheese called "tau-fu" from "Chinese caravances" (soybeans). Independence wasn't the only campaign of which old Ben was an early adopter.

City Tavern owner and executive chef Walter Staib said adding a tofu entrée was "one of the best decisions I ever made," as the dish has wound up "a top seller" at City Tavern.

The straight-off-the-menu version is vegetarian, but is breaded with egg and served on linguine that also has egg; the vegan alternative - which Staib noted "tastes just as good" - is a broiled tofu served on a bed of seasonal veggies.

Was it the letter that inspired the addition, or was that a convenient excuse to diversify the menu? Staib allowed that "I was getting a lot of requests for vegetarian options," and having researched the Franklin tofu issue, he decided the time was right to do something tasty with the information.

Our 'vegan' forefathers

So is this vegging up of historical menus stretching the notion of "authentic" to fit modern tastes and health concerns?

Not necessarily, Staib said. "In the 18th century, a lot of people were [plant-based eaters] not by choice, but by circumstance."

Addison concurred: In Colonial times, "there were a lot more vegetables and a lot more starches served" than present-day menus might indicate.

Even among those who had the means to feast on flesh, some intentionally cut back. Thomas Jefferson, a prodigious gardener, said he ate meat only "as a condiment to the vegetables which constitute my principal diet."

In the context of the times, he was a "near-vegan," said Staib.

So Franklin wasn't the only culinary visionary in Independence Hall. And as it happens, Jefferson was also mentioned as inspiration by Justin Addison, who noted that "Chef Rhys and I are eating more like that these days."

In fact, Traditions should have "an entire vegetarian and vegan menu" as early as next year.

All that Colonial-era reminiscing, and the pitching of independence to the man in the dirt street, got me musing: Just as explicit human rights slowly dawned on the popular mind in the face of traditional might-makes-right colonialism, might the logic of sentient-animal justice be slowly dawning on traditional "carnivore" foodies?

Too early to tell, but as we move forward, there's one thing you can count on.

"You're going to see more vegan restaurants," Staib predicted. "I think it's here to stay."

"V for Veg" chronicles plant-based eating in and around Philadelphia. or @V4Veg on Twitter.