You are mistaken; Using religious history is not part of the names nor constitutions of European Union (EU) states. Doing so would not be permitted by EU treaties and law.
Really? You mean like the constitution of Greece which reads, "In the name of the Holy and Consubtantial and Indivisible Trinity..."
Or Ireland: "In the name of the Most Holy Trinity, from Whom is all authority and to Whom, as our final end, all actions both of men and States must be referred, We, the people of Eire, humbly acknowledging all our obligations to our Divine Lord, Jesus Christ, who sustained our fathers through centuries of trial ... do hereby adopt, enact and give ourselves this Constitution."
Norway: "Our values remain from our Christian and humanist heritage."
Poland: "We, the Polish Nation – all citizens of the Republic, both those who believe in God as the source of truth, justice, good and beauty, as well as those not sharing such faith but respecting those universal values as arising from other sources, (...) beholden to our ancestors (...) for our culture rooted in the Christian heritage of the Nation and in universal human values, (...) recognizing our responsibility before God or our own consciences, hereby establish this Constitution of the Republic of Poland."