One of the most cherished traditions at Symphony Center is the annual holiday visit of the Vienna Boys Choir. Captivating millions worldwide, the ensemble is one of the world’s oldest and most celebrated choral groups. This season, the Vienna Boys Choir returns Nov. 30 for a program of folk songs, classical music works and holiday favorites.

Tina Breckwoldt, the choir’s official historian, reports that the group has always maintained a broad repertoire: “If you look back at programs from the 1920s, which is when the choir began touring on this scale, you will find operettas, singspiels, folk music and classics.”

Some fast facts about the Vienna Boys Choir:

Milestone dates: Historians have settled on 1498 as the founding year of the Vienna Imperial Chapel and thus the Vienna Boys Choir. In 1918, after the fall of the Hapsburg Empire, the Austrian government took over the court opera, its orchestra and adult singers, but not the boys’ choir. Josef Schnitt, who became dean of the Imperial Chapel in 1921, turned the choir into a private institution. The former court choir boys became the Wiener Sängerknaben (Vienna Boys Choir).

Classical connections: Composers including Mozart, Gluck and Bruckner have worked with the Vienna Boys Choir. Schubert was a chorister, and brothers Franz Joseph and Michael Haydn were members of the choir of St. Stephen’s Cathedral, but frequently sang with the imperial boys’ choir as well.

Sailor suits: Once overseen by the Austrian Imperial Court, the choir members wore military uniforms. Once the choir reverted to private control in the 1920s, the choristers began to wear sailor suits, then the height of boys’ fashion.

Their membership: The choir consists of 100 boys from the ages of 10 to 14, hailing from dozens of nations. The hundred choristers are divided into four groups, and each group spends nine to 11 weeks of the school year on tour, visiting nearly all European countries and frequently performing in Asia, Australia and the Americas.

Their education: Along with traditional academic studies, the boys focus on ear training, sight-reading, voice training, theory, instrument instruction, music appreciation and history. The choir maintains its own schools, where almost 400 children and teens from the ages of 3 and 18 study and rehearse at Augartenpalais, a baroque palace and former imperial hunting lodge in Vienna. At age 10, the most talented are selected to join the Vienna Boys Choir and then enter the choir’s boys-only grammar school.