BERLIN (AP) — A German court has ruled that a vast trove of art which a German collector kept hidden from the world for decades can go to a Swiss museum as requested in his will.

The Munich state court said Thursday that Cornelius Gurlitt's will is valid, rejecting a case brought by his cousin Uta Werner who claimed the 81-year-old wasn't mentally fit when he wrote it.

Gurlitt died in May 2014, months after German authorities announced they had seized more than 1,000 artworks at his apartment. His will designated Switzerland's Kunstmuseum Bern as his sole heir. A lower court rejected Werner's challenge and she appealed.

The Bern museum has pledged to ensure that any pieces looted by the Nazis before making their way into Gurlitt's collection will be returned to Jewish owners' heirs.