Chancellor Helmut Kohl's Christian Democrats and its Bavarian sister party, the Christian Social Union, are now demanding the lessons become compulsory, as almost everywhere else in Germany, and are taking their case to the highest German constitutional court in Karlsruhe.
The Catholic church has totally rejected the recent Brandenburg regional government decision to make religious education only optional, deciding instead to teach it outside of school.
The Protestant Church is temporarily willing to compromise with Brandenburg, allowing religious studies to remain an optional subject for now, but hoping to make it compulsory in the future.
Of some 1,247 schools in the region, which surrounds Berlin, only 240 offer religious education lessons at present. The Protestant church, the predominant faith in the area, is determined to reverse this trend.
Brandenburg lies in what was the former Communist East Germany. There religious education was limited if it appeared on the curriculum at all. It was scorned as part of the capitalist make-up. The west won. That is what is often proclaimed by east Germans who have lost out from unification or are unhappy with how it is developing. Attempts are being now made to replace the old Communist line towards religion by western politicians, despite meeting local resistance.
The religious education debate is just one of the areas in which old traditions in the east die hard, to be replaced by western role models. This is one of the many problems plaguing unification.
Brandenburg's Social Democrat (SPD) government is itself deeply divided on the issue. The government narrowly passed the religious education agreement recently.
Education minister, Angelika Peter, said a decision was reached only "after difficult and tough discussions", but admitted that the SPD had very mixed feelings about the matter. SPD spokesman, Michael Donnermeyer, said they had come to a "nail-biting" decision.
A possible compromise in the future could be teaching religious instruction alongside the compulsory ethical studies subject in the school curriculum. Ethical Studies is itself controversial. It is only taught in Brandenburg, as an alternative to religious studies, which is compulsory almost everywhere else in Germany.
Brandenburg protestant bishop, Wolfgang Huber, said the decision to make religious education only optional, "was a step in the right direction", but made it clear that "in the long-term it is not enough".
The Catholic church in the region has opted to teach religious education outside of the classroom, rejecting the government decision completely. They are waiting to see the ruling of the Karlsruhe Constitutional Court.
Religious education will be taught in Brandenburg schools, to classes between 12 and 24. The Brandenburg region will pay for 90 per cent of the costs, the rest paid for by the Protestant Church.