The Conservative Party chairman will today warn against the marginalisation of Christianity as she leads a delegation of seven ministers on an official visit to the Vatican.
Baroness Warsi will call for religion to be given a stronger influence on public life, arguing that faith has been a force for good both in Britain and Europe.
Her comments, on the eve of an audience tomorrow between the Pope and the ministers, follow a ruling in the High Court last week banning councils from saying prayers during meetings.
Speaking at the Pontifical Ecclesiastical Academy in Rome, Lady Warsi, a Muslim, will argue: "Europe needs to become more confident in its Christianity. Too often there is a suspicion of faith in our continent.
"It all hinges on a basic misconception – that to create equality and space for minorities we need to erase our religious heritage."
Ministers accompanying her include Jeremy Hunt, the Culture Secretary, Michael Moore, the Scottish Secretary, and Owen Patterson, the Northern Ireland Secretary.