Opus One Winery is a winery in Oakville, California, USA. The wine was called napamedoc until 1982 when it was named Opus One. The winery was founded as a joint venture between Baron Philippe de Rothschild of Château Mouton Rothschild and Robert Mondavi to create a single Bordeaux style blend based upon Napa Valley Cabernet Sauvignon. It is located across State Route 29 from the Robert Mondavi Winery. The creation of this winery venture in 1980 was big news in the wine industry; de Rothschild's involvement added an air of respectability to the burgeoning Napa wine region. The first vintage, 1979 was released 1984 at the same time as the 1980 vintage. For a while it was the most expensive Californian wine costing 50 USD.