When one of my sisters was born, my mother wanted to name her Nancy (not real names, of course) but the priest didn't like it, so he named her Lucy-Ann. Mother didn't know for a while that Nancy was not Nancy. And no one from the family that was there went against what the priest said.
Shades of Leo Milligan, father of the great Goon, Spike. His parents wanted him to be called Percy, but the priest at his baptism said "Call him Leo, after the dear Pope", so they did.
My Dad knew and Irish lady who needed her birth certificate to claim her state pension, but she had no copy herself, and the original record had been consumed in a fire in the 1920s. However, she got a copy of her baptismal record from the church where the ceremony was performed, and consequently, her pension.