In 1984, the "Festival of Winter Classical Concert Series" was created, with the proceeds benefiting local musical organizations like the Napa Valley Opera. Together with Veronica di Rosa, Margrit and a small group of other Napa Valley art lovers formed a board of directors to rebuild the original 19th-century opera house in the city of Napa. She organized fundraising events, including art auctions, to keep the opera house alive. In 1998, the opera raised significant funds for the restoration as part of a challenge grant from Margrit and Robert Mondavi; the renovated opera house opened in October 2002.