(OCRegister) - More than a century ago, California wine was hugely popular, not only domestically but all over the world. Yet only a few years later, the industry almost disappeared in the Golden State. Its principal savior? The Catholic Church.

Here’s what happened.

In the latter half of the 19th century, Europe’s wine producers fought a losing battle with phylloxera, a vineyard-destroying root louse introduced from America in 1863. Ironically, the American wine industry flourished because New World varietals were resistant to the pest. By the turn of the 20th century, thanks to savvy European immigrants, California had created a large wine industry with a global reach, and California wines were beginning to win prestigious international competitions.

But the American wine industry was soon felled by a man-made disaster.

In 1919, the Volstead Act and the 18th Amendment to the U.S. Constitution prohibited the “manufacture, sale, or transportation of intoxicating liquors.” Before 1920, the U.S. was home to more than 2,500 commercial wineries. Fewer than 100 survived Prohibition. Making wine for the Catholic Church was the principal source of income for many of them.

After Prohibition ended in December 1933, American winemaking was in a sorry state for many years. But the Catholic Church had the knowledge and resources to guide the devastated industry into the modern era.

Brother Timothy Diener, a high school teacher at the Institute of the Brothers of the Christian Schools, was transferred in 1935 to the order’s Mont La Salle in Napa Valley’s Mount Veeder region. While there, the large, athletic science instructor became a wine chemist and helped improve the order’s already-established wine business.

The Christian Brothers had provided sacramental wine during Prohibition, and under Brother Timothy’s guidance, the winery thrived as a quality commercial producer. It was considered one of the nation’s finest winemakers in those years, as well as one of the biggest. At one point Christian Brothers was producing about 1 million cases of wine annually and operated three wine-producing facilities in the Napa Valley.

In 1989, Christian Brothers’ Napa Valley operations, including the historic Greystone Cellars and 1,200 acres of vineyards, were purchased by the Heublein division of Grand Metropolitan PLC of Great Britain in one of the largest winery sales in U.S. history.