 Complete the following phrase:  In 1999, Al Bano announced their separation in an open letter to the weekly magazine Oggi, in which he explained reasons for their break-up as related to the disappearance of their daughter. The two reunited in 2013, reportedly only on a professional basis, for a concert performance in Moscow their first live performance together in sixteen years. They continued to perform live as a duo in 2014 and 2015, including at 