Ujm
Of course you have no proof to that statement
Yidden were sheltered in churches during times of upheaval
Yidden sent delegations to Rome , whether they were required to go to places they didn’t want to I can’t tell you
There is at least one case in the gemarah of a rav violating yichud in regards to an important matter
John of spryer saved Jews in his quarters on the “northern side of the cathedral “ granted that was straight out pikuach nefesh and I have no proof they entered the cathedral but this isn’t far fetched
If it wasn’t during prayers and it was a head of state whose benevolence helps Jews in galus, then I don’t find it hard to believe it hasn’t happened before
