South African composer Bongani Ndodana-Breen, who was commissioned by the orchestra to compose a Nelson Mandela tribute (photo provided by Minnesota Orchestra).

With hopes of taking another bold step across cultural boundaries, the Minnesota Orchestra has announced a "Music for Mandela" theme for its Sommerfest 2018 festival.

From July 13 to Aug. 1, 10 concerts will pay tribute to the great South African statesman Nelson Mandela on the 100th anniversary of his birth. The festival also will serve as a curtain-raiser for Minnesota Orchestra's pioneering tour of South Africa in August.

African musicians and their continent's rich choral tradition are strongly represented in the festival lineup. Minnesota Chorale will be joined by Insingizi, a vocal trio from Zimbabwe, for a "Celebrating Mandela at 100" program of South African choral music led by Minnesota Orchestra Music Director Osmo Vänskä (July 20). Vänskä also leads the festival's keynote "International Day of Music" concert (July 21) pairing Beethoven's Ninth Symphony with the world premiere of "Harmonia Ubuntu," a Mandela tribute by South African composer Bongani Ndodana-Breen. A quartet of South African soloists and local gospel choirs will join Minnesota Chorale for the occasion.

Other festival highlights include: a return visit by six-time Tony Award-winner Audra McDonald with a program of Broadway songs (July 13), the Orchestra Hall debut of the brilliant Canadian pianist Stewart Goodyear in Beethoven's Fourth Piano Concerto (July 27) and the Grammy Award-winning South African vocal group Ladysmith Black Mambazo (July 31).

Sommerfest 2018 concludes Aug. 1 with a "South Africa Tour Send-Off Concert," featuring the rare opportunity to hear Vänskä lead an all-American program including Gershwin's Piano Concerto and Charles Ives' Second Symphony.

The South Africa theme was inspired partly by the orchestra's historic trip to Cuba in 2015. After that "transformative" tour, musicians and leaders "definitely wanted to explore beyond the usual European and Asian venues," Minnesota Orchestra president Kevin Smith said earlier this year.

Another inspiration for the tour: Vänskä traveled to South Africa in 2014 to conduct the young musicians of the South African National Youth Orchestra and "came back raving about the whole experience," Smith noted.

Vänskä will lead the biggest Sommerfest 2018 concerts. No immediate successor was named to former Sommerfest music director Andrew Litton, who stepped down last year after 15 seasons.

Current Minnesota Orchestra subscribers can purchase tickets immediately by calling 612-371-5656 or visiting Individual concert tickets can be purchased beginning April 6.

Reporter Jenna Ress contributed to this report.