However, in April 2008, La Monnaie announced that Wigglesworth would not take up the position of Music Director, after reports of opposition to him from the orchestra. In June 2011, the company announced the appointment of Ludovic Morlot as its next Music Director, as of the 2012–2013 season, with an initial contract of 5 years. In December 2014, citing artistic differences, Morlot resigned from the La Monnaie's music directorship, effective 31 December 2014. In September 2015, the company announced the appointment of Alain Altinoglu as its next Music Director, effective January 2016. For performances of Baroque operas, La Monnaie mostly engages guest orchestras specialising in authentic performances on period instruments. Over the past decades, René Jacobs and his Concerto Vocale have been regular guests at the theatre. Dance and ballet always had their place on the stage of La Monnaie, and during a major part of its history, the theatre housed its own "Corps de Ballet". Several members of the Petipa family left their mark in Brussels in the 19th century, but the enthusiasm of the public for traditional ballet performances diminished in the 1950s. In 1959, director Maurice Huisman embarked on a cooperation with the young avant-garde choreographer Maurice Béjart. This resulted in the creation of the new Ballet of the 20th Century which became the theatre's new ballet company until 1987, when Béjart and his Ballet left La Monnaie after a conflict with Gérard Mortier. In 1988, Mortier hired the New York choreographer Mark Morris and his Mark Morris Dance Group. For three years, they were known as the Monnaie Dance Group Mark Morris. Morris directed several productions in Brussels until 1991. Under Bernard Foccroulle, Anne Teresa De Keersmaeker and her company Rosas became the dance company in residence.