Vladimir Shklyarov, a ballet star, tragically passed away at the age of 39 after falling from the fifth floor of a building, announced a representative from the Mariinsky Theatre.

According to the theatre’s spokesperson, Shklyarov fell on Saturday. The 39-year-old dancer had been taking painkillers for a back injury and was scheduled for spinal surgery on Monday.

Although an investigation is underway to determine the cause of the dancer’s death, “the initial cause is believed to be an accident,” according to Russian news agency RIA Novosti.

Born in St. Petersburg in 1985, Shklyarov joined the Mariinsky Theatre in 2003 and became its principal dancer—the highest position in a ballet troupe—in 2011.

The theatre issued a statement expressing condolences: “Our deepest sympathies to the artist’s family, his loved ones, his friends, and to all the many admirers of his work and talent… his name will forever be written in the history of world ballet.”

Throughout his 20-year career, Shklyarov starred in productions of “Swan Lake,” “Romeo and Juliet,” “Sleeping Beauty,” “Don Quixote,” and “Alice in Wonderland.”

In 2013, Shklyarov married his fellow dancer from the Mariinsky Theatre, Maria Shirinkina, with whom he had two children.