Several cultural milestones represent the top choices among the performing arts in the coming week.

Most interesting to Broadway aficionados is City Theater’s current production of “Company,” the Stephen Sondheim-George Furth musical that marked a major turning point in Broadway history. This fine community troupe has mounted a spirited production of this 1970 cultural landmark, which runs through two more weekends in Biddeford.

Ludwig van Beethoven’s “Emperor” concerto, a towering monument of the symphonic literature, rates top billing on the Portland Symphony Orchestra’s next concert on March 20. Guest conductor Ken-David Masur, one of three finalists for appointment as PSO music director, will take the podium, while guest pianist Natasha Pareski will take on Merrill Auditorium’s big Steinway.

DaPonte String Quartet resumes its 2017-2018 subscription season with five performances of a program focused on Viennese music in five venues stretching between Rockland and Portland.

‘Company’

To marry or not to marry? That is the question.

After nearly three hours, that Hamlet-like question still isn’t answered. The unresolved tension inherent in that ambivalence provides the subtle dramatic horsepower that drives “Company,” the milestone Broadway musical that deconstructed many of the accepted practices of American musical theater in the 1970s – and continues to the present.

“Company” rewrote many of the rules of musical stagecraft, and opened avenues for alternative formulations. It is considered Broadway’s pioneer “concept musical.”

City Theater, a fine community troupe, has mounted a spirited and energetic production that will run for two more weekends at the Opera House in Biddeford.

“Company” was the first Broadway musical to fully reflect the talent of composer and lyricist Stephen Sondheim. Set in Manhattan in the 1970s, “Company” is based on a series of short comic vignettes about love and marriage by playwright George Furth. In each, a 35-year-old bachelor named Robert is paired with a married couple. All of these marriages are dysfunctional in different ways, and Robert serves as both observer and dramatic foil.

“Company” unites Furth’s vignettes under a dramatic umbrella. Five couples gather for a surprise birthday party for Robert. Plus three of Robert’s girlfriends appear in various scenes and a four-character “vocal minority” pops up here and there to play bit roles and add power to songs and dances. Furth makes it clear that there is no linearity to his very anti-formulaic book: By design his little comic scenes seem to appear in random order. Sondheim wrote a song for each scene that reflects and intensifies the underlying theme of each.

Sondheim’s songs reflect both joys and foibles of love and help elucidate Robert’s slowly evolving views on marriage. “Marry Me a Little” is the most memorable of these, a musical commentary on Robert’s ambivalence to romantic commitment. Others include “Sorry-Grateful,” which introduces the underlying tension in marriage, “Another Hundred People,” which comments on the anonymity of life in a huge city, “Side By Side,” which is the show’s one rousing ensemble number, “Barcelona,” which depicts two facets of a romantic breakup, and “The Ladies Who Lunch,” a sardonic critique of New York’s cafe society.

The result was success. “Company” opened in April of 1970 and ran for nearly two years. It copped six Tony Awards, including Best Musical, Best Book and Best Score. It has been revived on Broadway in 1993, 1995 and 2005, winning an additional Tony for the latter.

City Theater artistic director Linda Sturdivant gets splendid, spirited performances from her cast of 18, led by Caleb Lacy in the difficult role of Robert. Among the supporting cast members, I especially liked Jennine Cannizzo as a cynical, oft-married middle-aged seductress, and Elizabeth Lester as Robert’s hippest and sexiest girlfriend.

City Theater presents “Company” through March 25 at the Opera House, 205 Main St. in downtown Biddeford with 7:30 p.m. performances Fridays and Saturdays and 2 p.m. Sundays. Call 282-0849.

Portland Symphony Orchestra

One of the best-loved pieces in the symphonic literature is the featured number in the Portland Symphony Orchestra’s upcoming concert. Ludwig van Beethoven’s “Emperor” concerto for piano and orchestra has been an audience favorite since it was first performed in 1811. Although it is today accepted as the gold standard of the piano concerto format, it was very revolutionary in its own time.

As Mark Rohr, the PSO’s longtime program annotator, explains: “Beethoven never wrote an ordinary concerto: There’s something unusual around every corner. While most concertos lay out the themes in the orchestra before the soloist enters, here the piano launches right in, only to fall silent. This deceit creates a certain tension about when it will re-enter. Later, at the place where we expect a to hear a cadenza, Beethoven specifically forbids one, instructing the soloist to push on.”

The PSO’s guest soloist will be globetrotting pianist Natasha Paremski. On the podium will be Ken-David Masur, who is one of three finalists for the position of the PSO’s next music director.

Two other longtime audience favorites will round out the program. The concert opens with an opera overture by Wolfgang Amadeus Mozart and wraps up with Antonin Dvorak’s Symphony No. 6.

Catch the Portland Symphony Orchestra at 7:30 p.m. March 20 at Merrill Auditorium at Portland City Hall. Call PortTix at 842-0800.

DaPonte String Quartet

The DaPonte String Quartet, Maine’s busiest classical ensemble, continues its 2017-2018 season with a series of concerts based on a Viennese theme. Five concerts represent a musical stroll through Vienna, home of the Prater, the world’s oldest amusement park, in company with some of the Austrian capital’s most powerful musical prodigies.

Each represents a different period and style of composition and each was a revolutionary in his own time. Franz Joseph Haydn was an innovator, who is credited as the inventor of the classical string quartet format. Prior to Haydn, small ensembles were typically dominated by one violin. Under Haydn’s reformulation, each of the four instruments have equal voices in presenting and developing themes and variations.

Ludwig van Beethoven was a revolutionary composer who reformulated the string quartet in more powerful ways. Alban Berg was another innovator whose experiments in harmony had long-lasting influences.

Here’s the schedule: March 18 at 3 p.m. at the Lincoln Theater, 2 Theater St., Damariscotta; March 22 at 7:30 p.m. at the Maine Jewish Museum, 267 Congress St., Portland; March 23 at 7 p.m. at the Rockport Opera House, 6 Central St., Rockport; March 24 at 4 p.m. at St. Columba’s Church, 32 Emery Lane, Boothbay Harbor, and March 25 at 3 p.m. at the Unitarian Church, 15 Pleasant St., Brunswick. Call 529-4555.

City Theater in Biddeford is running a spirited community production of “Company,” the milestone 1970 Broadway musical, through March 25.