[OLD REGGIE]

The perpetual virginity of Mary [...] didn’t make it into any of the three creeds because it was not doctrine! It was not necessary to believe for salvation!

No it is not "necessary for salvation" in the same sense as "I believe in God" is. But this part, "I believe in One Holy Catholic and Apostolic Church" is in the Creed, and comes without a disclaimer about "unless it is a historically known fact".

Please enlighten me as to just when "Holy Catholic and Apostolic Church" changed from adjectives to proper nouns in your Creed.

[annalex]

when "Holy Catholic and Apostolic Church" changed from adjectives to proper nouns in your Creed.

Holy, Catholic and Apostolic are adjectives and Church is a noun. Not a proper noun. Maybe I don't understand the question or don't know the English grammar well enough to answer.