Just as an introduction, Most Protestants believe in the Doctrine of the Trinity, even though the word Trinity is not mentioned in the Bible, and it is only illuded to, but never explicitly taught. It was a Council of the Catholic Church which defined, and expounded on the doctrine in part from the illusions to it in the Bible, and by the Oral Tradition which was passed from Christ to the Apostles. So much for the Protestant idea that something needs to be spelled out explicitly in the Bible to be doctrine. I chose this because your Saint’s name Patrick honors the great Apostle of Ireland, who proved the Trinity to the Pagans by the three leaf clover.
There are any number of things that Protestants do and believe that they got from the Catholic Church, the fact that later they rejected some of what their forefathers believed until the founding of Protestantism in the 16th Century, a full 1500 years after the founding of the Catholic Church by Jesus, upon the Apostles is something that most Protestants and many Catholics are unaware of. You will be able to seek out the answers to their questions here.
You may want to start with Jon’s article at this link….