The 1970 Hawaii wine conference planted the seed for Opus One, when Baron Philippe de Rothschild scouted Californian partners years before the 1976 Judgment of Paris. Robert Mondavi, fresh from a family lawsuit and eager to prove Napa's worth, signed a 50-50 pact in 1978 at Mouton's converted stables. The deal marked Bordeaux's first serious acknowledgment that Napa Valley could rival its finest growths.

Cultural friction defined the early vintages. Mouton's Lucien Sionneau spoke no English; Mondavi's son Tim spoke no French. Geneviève Janssens translated as the two winemakers initially produced separate wines, each insisting their method was correct. Yet the 1979 debut, labeled Napamédoc, fetched $2,000 per bottle at the inaugural Napa Valley Wine Auction — a record for American wine that signaled speculative fever more than critical consensus.

The market rejected Opus initially. Californians found it too French; the French dismissed it as an imposter. At a price far above any domestic rival, bottles gathered dust until a 1988 innovation — selling by the glass in miniature decanters — cracked restaurant resistance. By 2004, Opus One joined Almaviva as only the second non-Bordeaux wine on La Place de Bordeaux, the region's hallowed distribution network.

The partnership rewrote the rules for transatlantic wine investment. Christian Moueix followed with Dominus at Yountville, while Mondavi later replicated the model in Chile. What began as a baron's bedroom negotiation became the template for legitimizing New World ambition within Old World commerce.