The petition was presented Thursday at the Conference of Ministers of the Interior of the European Union on Interreligious Dialogue, which was addressed by EU Ministers of the Interior and representatives of several confessions.
Among the participants in the meeting, who were expected to have an audience with the Pope today, are Christian, Jewish and Muslim leaders.
Charlotte Knobloch, vice president of the Central Council of Jews in Germany, stressed the importance of "the mention of such roots and of God in the Constitution."
"Religious freedom is a fundamental element in Europe, and it must be a reality in churches, mosques and synagogues," said Knobloch, the leader of Munich's Jewish community.
Dalil Boubakeur, president of the French Council of Muslim Worship, said that Islam is the second religion of Europe, with 17 million practicing Muslims, which "is going through a difficult period."
"Its image is marred by terrorism and fundamentalism," the head of Paris' mosque said. He lamented the "politization of religion."
The conference seeks to find a way in which interreligious dialogue can help to combat terrorism and be a response to the challenge posed by the integration of immigrants.
At the opening of the meeting, Italian Interior Minister Giuseppe Pisanu said that the integration of immigrants will avoid their being exposed to the influence of fundamentalist groups, which at times take recourse to violence.
The meeting produced a draft of a "European Letter for Interreligious Dialogue" and of a plan for a "European Forum for Interreligious Dialogue Among European Governments and Religions." Pisanu said the proposals will be presented to the EU's Council of Ministers of Justice and of the Interior.