Ostritz, Germany ? The nuns at St. Marienthal Convent have weathered the toughest times imaginable in their 770-year history: the Reformation, the Black Plague, fires, a massive flood, the Nazi dictatorship and East German communism.

But it was a little over a decade ago — after the Berlin Wall came down and the two Germanys were made one again — that the convent faced what 69-year-old Sister Hildegard Zeletzki called its toughest choice: going public.

“That was the crunch point,” she said.

The Roman Catholic convent had fallen into serious disrepair under decades of communism. For the 15 remaining nuns to keep operating the sprawling site, they would have to dive into the new service-oriented economy — remaking the convent as a postcard-perfect tourist destination.

“For centuries we were completely alone here,” Zeletzki said. The nuns asked themselves, “Can we do this? Do we want to do this?” Then came “How do we do this?” she said.

The answer was to abandon most of the agricultural endeavors that had sustained them in East Germany and reinvent their home as a center that combines guesthouses, a nonprofit, international meeting facility and a host of eco-friendly projects.

Bolstered by nonprofit and government funding, St. Marienthal has now transformed from a quiet, dilapidated nunnery into a driving motor for the local economy — a symbol of success among the struggling states of the former East Germany.

“Like in the Middle Ages, it’s a cultural center and an economic center,” said 56-year-old Bodo Bergmann, a craftsman from Duerrhennersdorf who recently sold handmade textiles at a fair at the convent, one of several the nuns host each year.

The convent sits on the Neisse River, directly across from Poland and a short drive from the Czech border. It’s a prime location for the convent’s international meeting center, which aims to promote peace and understanding in the region and beyond, with seminars and other events that draw 20,000 each year.

Every summer, survivors of Nazi persecution come to the international center to pass on their stories to the newest generations of Czechs, Poles and Germans.

“They try to work through the past, because the young people can’t imagine it,” Zeletzki said. This summer marks the first time the center will host a Jewish group of survivors to share their stories.

Added to that are a slew of tourists out for an affordable, relaxing and perhaps religious-oriented vacation. Guests can visit the convent’s small vineyard or stroll in its garden of biblical plants that fare well in the German climate and soil. Guided tours bring visitors to the nuns’ small, ornate church, where some of the convent’s abbesses are buried.

All the foot traffic has meant some adjustment for the nuns.

“The older sisters had it somewhat harder than the younger sisters,” said 48-year-old Sister Elisabeth Vaterodt. Yet even some of the more reluctant nuns have begun giving tours — “something unimaginable 20 years ago,” said Vaterodt, whose portable phone now seems as much a part of her uniform as her black and white habit.

Areas like the nuns’ living quarters and late 17th century library remain off limits, and Vaterodt insists that — thanks to thick walls — the Cistercian nuns can go about their strict regimen of prayer without disruption.

In a region where unemployment is more than 20 percent, the convent employs some 150 workers to help it run its operation, and jobs aren’t the only thing the nuns have brought their neighbors.

The convent also is a “clean” energy supplier, pumping electricity generated by solar, wind, hydroelectric and biological waste recycling projects into the area’s power network. In 2000, the neighboring town of Ostritz, with about 3,400 residents, became the first in Germany to be fully powered by renewable energy — a marked change from East German times, when coal production took a heavy toll on the local environment.

The one area in which the sisters are still looking for success is in replenishing their own numbers. Today, the youngest nun is 31.

Zeletzki said she isn’t overly worried. “That is a question of hope,” she said. “Because Christianity, I think, is a religion of hope, I have absolutely no fear.”