In the Lutheran Church, Reformation Day is a celebration of Martin Luther's historic act of nailing the 95 Theses to the doors of the Castle Church.

Four hundred and ninety-one years later, the South Hills Lutheran Cooperative Ministry is bringing together congregations from eight area churches for its second annual combined festival service this Sunday.

"We are looking for ways for [our churches] to cooperate. Most have dwindled in size and there are two things we have addressed," said the Rev. William Hower, interim pastor for the past three years at the Church of the Redeemer in Carrick.

"First, some can't afford to have a full-time pastor, and second, we don't have enough young people to have the kind of youth ministry we'd like."

Joining forces for the festival service a year ago was one of the first efforts by the cooperative ministry.

"It was a big success. We combined the musicians from all of the churches, who sang for the service," the Rev. Hower said.

Other churches involved are Holy Trinity in Beechview, Bethlehem, Allentown; Grace, South Park; Trinity, Mount Oliver; Prince of Peace, Pleasant Hills; North Zion, Baldwin Borough; and Stewart Avenue Evangelical Lutheran Church, Carrick.

Sunday's service at Stewart Avenue, which will be preceded at 6:30 p.m. by a half-hour concert by the Tuetonia Mannerchor and Damenchor Chorus of Pittsburgh, will feature songs and hymns sung in German.

Presiding over the service will be Bishop Kurt Kusserow of the Southwestern Pennsylvania synod.

The religious holiday of Reformation Day technically is Oct. 31, but many churches now observe Reformation Sunday.

Historians note that in 1571, Martin Luther hoped to spark public debate over Catholic Church doctrine when he nailed the proposal to the door of the church in Wittenberg, Germany.

Instead, it was viewed as an act of defiance, and he was excommunicated from the church three years later.

"What he actually wanted was to have a debate, but it touched off a brush fire," the Rev. Hower said.

"The Reformation is still a very, very prominent and important moment [in our church]."