My self-confidence as a Latin scholar was badly shaken after I took an 8-month immersion course in German, but I believe ex demands the ablative, and the ablative of Maria is Maria. I think you heard wrong, Jerry. Mariae is genitive or dative or nominiative plural. Prepositions are followed by nouns in the accusative or ablative case, depending on the circumstances.
But you did point out something I missed, Jerry - I'm almost sure it should be ex Maria Virgine.
Still and all, I wonder if there was any value in the six years of Latin I took. I shoulda taken Spanish.
-Joe Offer, still looking for correct lyrics for this song-