He married Anna Maria Chiaveri née Schulteiss, a widow who came from a family of southern German merchants from the city of Donaueschingen.
In the 1960s, Kopelent became well known in contemporary European music circles, with his compositions being performed at such festivals as the Warsaw Autumn, Donaueschinger Musiktage, Witten music festival and the annual festival in Darmstadt.
In 1975, performances of his work for large ensemble Transit and Time and Motion Study III were given; the former piece being awarded a Koussevitzky prize, the latter performed at the Donaueschingen festival.
Instead of the original chamber music series, the National-Socialist party organized its own concerts from 1933 to 1935, called 'Donaueschingen Musical Celebration' or 'Old and new chamber-music from the Swabian-Alemannic region'.
The city is situated at around 750 meters above sea level on the Baar plateau on the eastern edge of the southern Black Forest in the valley of Breg, about four kilometers south of Donaueschingen.
This predella was located in the Fürstenberg collections at Donaueschingen and was sold to Reinhold Würth in 2003, with the majority of the older German pictures.