Just when you think Gerhard Richter’s artistic legacy cannot possibly grow any bigger in Germany, it does.

The world-famous—and extremely busy—artist is designing three stained glass windows for Germany’s oldest monastery church. The 87-year-old painter’s design is due to be unveiled on September 4, and production will begin immediately, so the windows can be installed over the course of the next few months in the Benedictine Tholey Abbey, in Saarland, western Germany.

The church, which dates back to the 5th century, is undergoing restoration, so it is likely the windows will not be fully unveiled until the summer of 2020. In the meantime, to satisfy curious locals, the church is due to unfurl banners showing Richter’s designs on the building’s exterior in two weeks.

It is not the first time that the artist has created a new work for an historic church. Richter’s Cologne Cathedral Window is installed at the eponymous cathedral. Unveiled in 2007, the window measures 106 square meters (1,100 square feet) and consists of more than 11,000 glass squares in 72 colors that are randomly arranged.

The €370,000 ($410,000) cost of the Cologne commission was met by 1,200 donors. The artist did not accept a fee. Tholey Abbey told artnet News that the project is financed by a private investor.

The Benedictine abbey of Tholey in Saarland. Courtesy Wikimedia.

The press statement about Richter’s commission mentions a partnership with and his friend, the Estonian composer Arvo Pärt. Richter and Pärt have collaborated since 2015, most recently on an immersive live performance at the Shed in New York’s Hudson Yards, which closed on June 2. Pärt will also make a new work for the monastery church, but details of the project remain under wraps.

The Benedictine abbey of Tholey was first mentioned in texts as early as 634 AD, making it the oldest church in Germany.