Czechs Name Playwright as President : East Bloc: Vaclav Havel is unanimously elected by Parliament to become the nation’s first non-Communist leader in four decades.

PRAGUE, Czechoslovakia —  Parliament today crowned the nation’s peaceful revolution by electing playwright and opposition leader Vaclav Havel as Czechoslovakia’s first non-Communist president in 41 years.

In an unprecedented public vote that was televised nationwide, the Communist-dominated Parliament, or Federal Assembly, unanimously chose Havel, who was jailed for five years by the previous hard-line Communist leadership for speaking out against totalitarianism.

“I will not disappoint you, but will lead this country to free elections,” Havel told hundreds of cheering supporters from a balcony of the presidential Hradcany Castle after his election.

“This must happen in a decent and peaceful way so that the clean face of our revolution is not sullied,” he said. “It is a task for us all.”

The election of Havel, 53, is the crowning achievement of the popular revolt that began only 41 days ago. It comes amid democratic reforms in Poland, Hungary, East Germany, Bulgaria and Romania.

Havel and his wife, Olga, later walked across the courtyard from the castle to the St. Vitus Cathedral for a special Mass of thanksgiving given by Czechoslovakia’s 90-year-old Roman Catholic prelate, Cardinal Frantisek Tomasek.

At the entrance to the Gothic cathedral, several young girls presented Havel with bouquets of white lilies.

“We came to St. Vitus . . . to thank God for the great hope that has opened before us in the last days of this year,” Tomasek told the crowd.

The cathedral was filled with Antonin Dvorak’s “Te Deum” played by the Prague Philharmonic and choir after the short service.

The lawmakers’ meeting was opened by Alexander Dubcek, champion of the “Prague Spring” reforms crushed in 1968. He was returned to power Thursday when Parliament elected him Speaker of the body.