Cambridge’s legendary Irish pub The Plough and Stars — historically a popular hangout for writers, architects, and musicians alike — is celebrating its 50th anniversary this year. Co-founder Peter O’Malley and his son Gabriel joined WGBH News’ Henry Santoro of Henry in the Hub to discuss the bar’s history. The transcript below has been edited for clarity.

Henry Santoro: The Plough was the first place where I was served the perfect pint of Guinness. If it's poured correctly, it's a beer you have to wait for, isn't it?

Peter O’Malley: Correct.

Santoro: And why is that?

O’Malley: It's the way it's composed. There's a gas in it, and the gas makes it frothy. And you have to let it settle, and you have to move the glass at a 45 degree angle so it won't get over-foamed. And the great thing about Arthur Guinness — outside of him coming and fixing things for us — was he would buy everybody in the bar a pint. So they all looked forward to the Guinness man coming. We sold more Guinness, Harp and Bass than the rest of the East Coast of America combined.

Santoro: I am not surprised. Fifty years ago, the United States put a man on the moon, 350,000 people went to a music festival called Woodstock, The Beatles recorded “Abbey Road,” and thousands of people converged on Washington to protest the Vietnam War. There was certainly no shortage of things to talk about in a bar, was there?

O’Malley: You must remember at that time in Boston, you had great changes going on, particularly in the newspaper business, and also you had a group of young Turks in architecture called CambridgeSeven. So the Plough became a meeting place with these disparate people, disparate professions, who were extraordinarily brilliant in their own way and full of change. And we got George Kimball in, who spent a lot of his time dropping his glass eye into the beer mug to frighten ladies.

Santoro: At the Plough and Stars, I’ve seen Bonnie Raitt, Morphine, Treat Her Right, and G. Love & Special Sauce. I was there for Jeff Buckley, and of course, John Lincoln Wright was a fixture.

O’Malley: The man you left out was a favorite friend of mine — he was just in town — called “Spider” John Koerner.

Santoro: Sure. But let me ask you this, though: Didn't “Van the Man” Morrison spend a fair amount of time in the Plough?

O’Malley: He did, yes. Back in ’69.

Santoro: And the rumor is that he wrote some of “Astral Weeks” there.

O’Malley: Yes, that's a rumor. And the thing about rumor and myth is you might as well go with them. The last thing about the Plough that's more important than anything else is not so much the ownership — it’s the customers, and the customers are fantastic.

Santoro: Because of its location, it was a tremendous mix of the hippies of Harvard Square and the brainiacs of MIT.

O’Malley: And law students from Harvard Law School.

Santoro: And the law students from Harvard. And they all intermingled and intermixed at The Plough and Stars, and they enjoyed great music and great food, and of course, great conversation. Does a place like the Plough plan a big 50th anniversary celebration, or is it just business as usual day in, day out?

Gabriel O’Malley: The question is, 'Why limit it to one?' We've had a series of events over the year, and we put on a four-day birthday party event in April, which was really wonderful. We had some of our favorite artists from over the last 15 or 20 years, including Andrea Gillis and Vapors of Morphine, which is the latest iteration of Morphine. And we also had Will Dailey come, who has both toured nationally and is a local artist.

Santoro: Gabriel and Peter O'Malley aren't just two guys affiliated with The Plough and the Stars in Cambridge. They are The Plough and the Stars. So gentlemen, happy 50th – here’s to 50 more.