In Philadelphia, you don’t have to look hard to find an Irish bar — and we’re not just talking about the first half of March, when drinking establishments of all kinds dress up in shamrocks for a chance to get in on lucrative St. Patrick’s Day revelry.

Irish bars are the most prevalent kind of tavern in the city, from the themed pubs of Center City to the corner tappies that dot the neighborhoods. A sampling from a three-square-mile swath of Northeast Philly turns up Daly’s Pub, Quinn’s, Pat’s Pub, Leneghan’s Irish Pub, Harrington’s Pub, JJ’s Irish Pub, McNally’s Tavern, Tom Foolery’s Irish Pub, Curran’s Irish Inn, Scruffy’s Irish Pub…and the list goes on.

That’s not entirely surprising, since Philadelphia has the largest Irish population of any big city in the U.S. — around 220,500 people, according to 2013 census numbers. (Boston has a higher percentage, 20 versus 14 or so, but a lower overall population.)

But Irish pubs aren’t just a Philly thing — they dominate global drinking culture. There are Irish pubs in Nigeria and Irish pubs in Azerbaijan. In Argentina. In Indonesia. There’s an Irish pub at the base of Mt. Everest. The same can’t be said for a German beer hall or English brewpub or Scottish whisky bar.

How did Irish pubs take over the world? A combination of two complementary factors: Good marketing and good cheer.

Guinness and the ‘Irish Pub Concept’

Tim Herlihy is the U.S. brand ambassador for the Tullamore DEW, and for a recent seminar at national booze conference Tales of the Cocktail he researched the origins of Irish pub spread.

He traces the start of the trend back to a Guinness sales plan in the late 1980s. The folks running Guinness noticed that while sales in other parts of Europe were good, distribution was not — their dry stout only sold well in bars that were Irish-themed. So they made a concerted effort to get more Irish-themed bars built.

The first big push came in the lead-up to the 1990 World Cup, which was held in Italy. A team of six Guinness sales reps traveled the country meeting bar owners and potential publicans.

“They were like, ‘Listen, Irish fans are going to come here and watch the matches, and they’re great drinkers,’” Herlihy recounts. So, “‘if people want to watch sport, Irish pubs are the best environments.’”

He’s laid eyes on some of the brewery reps original sales documents, which showed that revenue at Irish pubs would be higher than typical bars and that the beverage-to-food ratio would also be higher (meaning higher profit). The pitch worked; from January to June 1990, no less than 58 Irish pubs were launched across Italy.

Around the same time, a Dublin architect named Mel McNally also had the realization that the Irish pub was a packagable concept. He came up with a set of five core pub designs, and began selling them to builders and restaurateurs around Ireland and the UK under the brand name “the Irish Pub Company.”

In 1990, the two like-minded companies joined forces, and the big export push began in earnest. By the end of the decade, the Irish Pub Company had helped open 2,000 themed taverns across Europe and hundreds in the United States, either by shipping pre-fabricated bars or simply providing architectural and business plans.

Not everyone loves the idea of cookie-cutter bars that are backed by a huge alcohol company.

As Irish Pub Company-backed Fadó planned to open in Philadelphia, many Irish bars in the area — including McGillin’s and the two Irish Pubs on Walnut Street — organized a boycott of Guinness because they thought it was unfair of a brewing giant to “help” one bar while others were pouring its beer. They still do not pour Guinness to this day, choosing instead to offer a different stout.

But for many people, even a pre-fab Irish bar is better than nothing.

“Those bars are like a ‘pub in a box.’ But I guess I would rather have a ‘pub in a box’ than no pub at all,” says Fergus “Fergie” Carey, co-owner of Fergie’s Pub and three other bars in Philadelphia.

‘Craic’ and the Irish habit of having a good time

Most of the Irish bars in Philadelphia — all those taprooms in the neighborhoods — are not backed by the Guinness corporation. They’re just an organic outgrowth of Irish culture.

“There’s always been an insane amount of pubs per capita in Ireland,” notes Herlihy, who is a native of Terminfeckin, a small village in Ireland’s County Louth. “There’s a really strong brewing and distilling culture in Ireland — there are breweries and distilleries in every tiny town — so once you have the liquid, then you need the establishment.”

There’s even a Gaelic term to describe the idea of communal fun: “Craic” (pronounced “crack”). When huge numbers of Irish emigrated from the European island to other parts of the world — there are around 6 million people living in Ireland, while the diaspora numbers around 80 million — they brought that craic with them.

According to Herlihy, the defining characteristic of a true Irish pub is that “it’s friendly in a non-pretentious way.” The best of them are small, he says, and usually narrow, so that even if there are only a few people inside, there’s an instant fun atmosphere. Even if the bars are larger, they’re equally welcoming to a businessperson looking to unwind and what Herlihy lovingly refers to as a “degenerate.”

“We could walk into an Irish pub and have a meeting over a drink,” he says, “or we could sit at the bar and get totally scooped. It’s the quintessential bar. The French have the cafes, the Italians have the restaurants and the Irish have the pubs. I’m oversimplifying, but generally, it’s true.”

Fergie agrees. “Whose bar would you rather go to — a French guy’s, a Polish guy’s, an Israeli guy’s or an Irish guy’s?” says the Dublin native. “We’re known to be fun, witty and hospitable. Party on.”