Conductor Nicholas McGegan is a generally genial soul. But he has little patience for the notion that there ever was — or still is — a feud between musicians who perform 17th- and 18th-century music in so-called authentic style on period instruments and those who don’t.

“I’m not sure where that might have come from,” said the British conductor, who will lead the Chicago Symphony Orchestra in a program of Handel, Haydn, Bach and other Baroque composers on Feb. 13 and 18. He also will conduct the Beyond the Score presentation titled “Mr. Haydn Goes to London” on Feb. 14 and 16.

Though McGegan now conducts a wide range of repertoire all over the world, he started his career 40-some years ago as a baroque flutist performing with ensembles headed by Christopher Hogwood, a dominant figure in the period-instrument movement. “I don’t know that the actual musicians who perform on period instruments have ever been that rigorous,” he said in an interview from his home in Berkeley, Calif., where he spends much of his time as music director of San Francisco’s distinguished Philharmonia Baroque Orchestra. “It makes good marketing for certain period instrument orchestras to pretend to be a little more holier-than-thou than they actually are.”

At any rate, while early music partisans may once have argued that large 21st-century orchestras can’t possibly do justice to Bach and Handel, who wrote for much smaller orchestras and less muscular instruments,  McGegan insists that argument no longer resonates. “An awful lot of players in regular symphony orchestras have had a go at playing period instruments,” he said. “The younger ones have actually been exposed to all that [in music school]. It’s no longer sort of two warring camps — not that they really were; that was all a great invention.”

McGegan does credit the early-music movement with one great advance: resurrecting long-neglected works that deserve to be heard by contemporary audiences. “At least for recording and radio, the period instrument movement has brought an awful lot of repertoire into the mainstream,” he said. “The number of Vivaldi violin concertos you can hear now is incredibly large, whereas 20 years ago, you could maybe hear 10, of which four were The Seasons. Now everybody’s producing a new unknown Vivaldi disc every two seconds.”

CSO audiences will hear samples of that unknown Vivaldi in McGegan’s concerts. His soloist will be mezzo-soprano Vivica Genaux (left), an Alaska native who has become of one of the world’s leading singers of Baroque and bel canto opera.  She will sing an aria from a 1732 Vivaldi opera, La fida ninfa (The Faithful Nymph) as well as arias from operas by much less well-known Baroque composers: Nicola Porpora and Riccardo Broschi, the brother of the famed castrato Farinelli.

“This is all a first for the Chicago Symphony,” said McGegan, “and it’s terrific. Vivaldi is a very famous composer, and Vivaldi opera? Wonderful.”

Along with instrumentalists, a growing number of contemporary singers like Genaux have been captivated by the renewed focus on Baroque music. [The period instrument movement has] “spawned a whole new generation of singers who love singing this stuff and who sing it beautifully,” McGegan said. “Vivica is probably one of the most glamorous examples. There’s [countertenor] David Daniels. Who would have thought of the great American countertenors 40 years ago? There was one — Russell Oberlin. Now there are lots of them and they’re singing all over the world.”

But the modern orchestra has influenced early music ensembles for the better as well. “There’s a tremendous level of professionalism,” he said, which has rubbed off on their early music counterparts. “There was a certain thing with period instrument orchestras when they first got started,” he said, a smile creeping into his voice. “One might have mistaken them slightly for a Berkeley protest movement. And believe me, you’re talking to me in Berkeley. I know of what I speak.”

As deeply researched Baroque performance practice began cross-pollinating between modern orchestras and period groups, the latter spruced up their acts a bit, according to McGegan. “The symphony is a thoroughly professional outfit,” he said. “So what you’ve got now, say, with my period instrument orchestra, is that we do run very professionally and we do wear tails. We have all the trappings of a modern symphony orchestra; we just happen to be playing period instruments. And what you get in the CSO, is there they are, playing fantastic arias from Vivaldi operas. So everybody wins.”

With his infectious enthusiasm and sly British wit, McGegan is looking forward to two additional concerts with the CSO this month: Beyond the Score programs Feb. 14 and 16 focusing on Haydn’s two, highly successful visits to London in the 1790s. McGegan will lead the CSO in excerpts from the Symphony No. 100 in G Major (Military) in the program’s first half and conduct the entire piece after intermission.

This is McGegan’s fourth visit to the CSO, and each has been marked by memorable events. In April 2011, he presided over concerts that paired the CSO with Hubbard Street Dance Chicago. On his first CSO engagement, in October 2005, he saw the city-wide celebrations and parade that greeted the White Sox after the team won its first World Series in 88 years. And in November 2008, his CSO visit coincided with the night that Barack Obama won his first presidency.

“I went to Grant Park with several other million people,” McGegan said. “That was the most glorious experience, to be with that crowd and just to be part of American history. I’m hoping for something very special,” he said of his upcoming visit to Chicago.

No ticker-tape parades or Election Night fireworks are on tap. But some other miracle might occur. In this seemingly endless winter, maybe the snow will hold off and the temperature will stay above zero. Now that would be something special, indeed.

Wynne Delacoma, former classical music critic of the Chicago Sun-Times, is a freelance arts writer and lecturer.