Regaled as the grand "ambassadors" of traditional Irish music, The Chieftains will get St. Patrick's Day festivities started early in Massachusetts with performances at Worcester's Hanover Theater (March 9), the Amherst Fine Arts Center (March 10), and the Lowell Auditorium (March 11). The band also has collaborated with Ry Cooder to produce a new album, "San Patricio," inspired by the story of the San Patricio Battalion of Irish-Americans who deserted the United States Army to join the Mexican side in the Mexican-American War of 1847. Guest stars on the album include Linda Ronstadt, Liam Neeson, Moya Brennan, Carlos Nunez, Los Tigres del Norte and a host of other celebrated Mexican, American, and Irish musicians and singers.

Last month, as he and his fellow Chieftains prepared for the start of the tour, co-founder and long-time guiding spirit Paddy Moloney spoke with the Boston Irish Reporter:

Q. Paddy, what's the line-up we can expect to see at your Massachusetts shows?

A. Right now, it's Matt Molloy, Kevin Conneff, and myself. Sean Keane is still with the band, but he doesn't like long tours so he won't be joining us for most of the dates. Still, once a Chieftain, always a Chieftain! We will, of course, have a number of guests: John and Nathan Pulaski – Jon's a wonderful fiddler, and Nathan does the Ottawa Valley style of dancing; Deanie Richardson, a great bluegrass fiddler; Jeff White on guitar, who is Vince Gill's right-hand man. We have the princess of dance, Cara Butler – Jean Butler's sister – and she's been with us for 17 years now, hard to believe. We also have Triona Marshall, a wizard of a harp player. There'll be one of your local pipe bands as well. We're still confirming some of the other guests who'll be appearing, but it'll a big hooley, that's for sure.

Q. And you'll be including material from "San Patricio," right? How's that part of the show shaping up?

A. We actually played it at the Celtic Connections festival in Scotland last month, and brought along some of the Mexican performers with us. Ry Cooder wasn't sure about it; he said, "I'll play 'Sands of Mexico' [a song he wrote for the album] and they'll all leave." But everything went very well. So now it's all icing on the cake – we know that anything on the album is possible to perform live.

Q. Talk about how the idea for the "San Patricio" album came about. It took a while to come together, didn't it?

A. I've been thinking and talking about the San Patricios for so long that it almost feels like I was there myself. But I came onto this story by accident. Some years ago, I was asked to do music for a project on the Civil War; as we know, the Irish fought on both sides. My friend who was doing the project, however, started talking about the US-Mexican War – which set the stage for the Civil War – and he mentioned this Irish brigade that had fought against the Americans.

That started the whole thing. I was just fascinated by this story, and not only by the story itself but also why it was so largely untold, because it has so many elements to Irish history. I mean, you have Irishmen coming to America to escape the Great Famine, and many of them get conscripted practically right off the boat. Some of them enlisted, of course, but once they got there they found the situation was very different than what they'd been led to believe: the living conditions were terrible, there was anti-Irish, anti-Catholic bigotry, and what's more, they were being told by Protestants to kill and conquer other Catholics. And the fact that this war involved taking land, well, that felt all too familiar to the Irish.

I mean, it was all just fascinating. You had John Riley, a native Irish speaker who had been a good soldier for the US army, and he winds up leading the San Patricios. They make this heroic last stand at the convent of San Pablo in Churubusco, knowing that if they lose they'll most likely be executed – and most of those who survived the battle were in fact hanged. Those who weren't, like Riley, were branded with a "D" – for "deserter" – on their cheeks and left to stay in Mexico.

Q. It's a complicated story, isn't it, perhaps especially for Americans? On the one hand, the Irish certainly had reasons to be unhappy with their situation, but in the end they took up arms against the country for whom they had been fighting; that might be difficult for some people to accept.

A. Well, I don't point the finger at anyone. We all have our faults, we all have things in our past we're not proud of. I simply felt that, here was this incredible chapter in Irish history that hardly anybody ever talked about, and it's left to your imagination: These men were thousands and thousands of miles from home, fighting a war they knew nothing about, they were probably never going to see their families again – can we know what that feels like? It also is part of the Irish diaspora, how the Irish have left their mark throughout the world. That's what I found as I traveled around Mexico: You hear some similarities in the music, the mazurkas, the jigs, the polkas; there's a song on the album called "Persecucion de Villa," and the melody is similar to one of our Irish rebel songs, "Kevin Barry."

Q. So the project became more than just a reconstruction of where and when this or that battle took place?

A. Exactly. Some of what's on the album, like "Sands of Mexico," is related directly to the San Patricios. For instance, there's a track called "March to Battle," with a narration by Liam Neeson over the tune played by the Banda de Gaitas de Batallón de San Patricio, which is the only pipe band in Mexico – it was founded in 1997 on the 150th anniversary of the Mexican American War and in homage of the San Patricio battalion.

But as I got further into the project, and I heard all these lovely sounds from several different regions of Mexico, I realized there was so much to tell, and I began involving more and more people. Carlos Nunez, for example, a bagpiper we've worked with on a number of occasions who plays the music of Galicia, which is very much in the Celtic realm; now, in the harmonies and the fandango and jig-like rhythms, Galician and Mexican music often sound similar. So here's yet another route that Celtic music has taken to North America.

And a lot of the album comes down to the role traditional music has in our lives, our cultures, wherever we're from. At one point, Ry and I were jamming with some of the Mexican musicians, and we had a lovely time, and I began talking about my grandmother growing up in County Leith, with no electricity, and how you'd spend the time telling stories and singing songs until the melodeon came down from the shelf. And that is exactly the same kind of story they had from their families.

Q. So it's quite a supporting cast you have on the album?

A. Ry – I found out his great-grandfather had been conscripted by the Union Army in the Civil War – is wonderful. He kicked in with his song and gave us a lot of support and encouragement. He said, "If you don't do this, I will." Lila Downs, who's on the first track, is very interesting. She grew up in Mexico and the US, got her degree in voice and anthropology, and she has this incredible knowledge of native Mesoamerican music. We were very happy to work with Chavela Vargas, who is 91 and has been a big influence to so many, especially in her rendition of rancheras. Los Tigres Del Norte are hugely popular in Mexico and have sold millions of albums, also won five Latin Grammy awards.

Los Cenzontles, Los Folkloristas, Los Camperos de Valles, the mariachi band Mariachi Santa Fe de Jesus – it was wonderful to get to know them all.

And, of course, there was Linda Ronstadt, who was very helpful, and Moya Brennan, from Clannad, did a lovely job on the "Lullaby for the Dead," which was written by Brendan Graham, who composed "You Raise Me Up." Liam Neeson was very moved by the whole thing; after he did his narration, he said, "If anyone's ever going to make a film about this, I want to be John Riley!"

Q. You won't be playing in Boston this time around, but from what I understand it used to be a "home away from home" for you?

A. I had a house near Commonwealth and Beacon for several years when my son was going to MIT, so he'd have someplace to stay – he went on to become the first Irish rocket scientist. Boston is my favorite city in the US. I have great memories of playing at The Orpheum in a concert with Siobhan McKenna, and at Symphony Hall – I think Sean Potts accidentally dropped his tin whistle into the piano at one point.

Q. It's almost 50 years that The Chieftains have been around, right? I think there have been 10 different presidential administrations during that period. Have there been times when you guys thought, "It's been a good run, but maybe we should just pack it in now"?

A. [Laughs] Well, you know, my wife says, "He's 10 years rehearsing for retirement." The music is still what keeps me going, and being able to work with such good friends. "San Patricio" just gave me a boost. It's been an incredible experience.