Thank you, Rokke, for taking the time to read the information at the link posted. The author's approach to "sola scriptura" christians, may well be perceived the wrong way. You noted:
I am left with the overwhelming impression that the most important element of Catholic (with a capital "C") faith is faith in Catholicism.
Actually, the Catholic faith is built on the Nicene Creed, and is fully expressed with solid scriptural references in the CATECHISM OF THE CATHOLIC CHURCH , which begins with a statement of faith.
SECTION ONE
"I BELIEVE" - "WE BELIEVE"
26 We begin our profession of faith by saying: "I believe" or "We believe". Before expounding the Church's faith, as confessed in the Creed, celebrated in the liturgy and lived in observance of God's commandments and in prayer, we must first ask what "to believe" means. Faith is man's response to God, who reveals himself and gives himself to man, at the same time bringing man a superabundant light as he searches for the ultimate meaning of his life. Thus we shall consider first that search (Chapter One), then the divine Revelation by which God comes to meet man (Chapter Two), and finally the response of faith (Chapter Three).
As Pope John Paul II notes, in the introduction to the Catechism:
GUARDING THE DEPOSIT OF FAITH IS THE MISSION WHICH THE LORD ENTRUSTED TO HIS CHURCH, and which she fulfills in every age.
As to the question you posed to Cronos ...
But no evidence exists that Peter was ever in Rome, that I'm aware of
Admittedly, the Bible nowhere explicitly says Peter was in Rome; but, on the other hand, it doesn’t say he wasn’t. Just as the New Testament never says, “Peter then went to Rome,” it never says, “Peter did not go to Rome.” In fact, very little is said about where he, or any of the apostles other than Paul, went in the years after the Ascension. For the most part, we have to rely on books other than the New Testament for information about what happened to the apostles, Peter included, in later years.
At that point, we turn to the EARLY CHURCH FATHERS , the first christians who bear witness to the works of the apostles. Now the 'big picture' emerges, with more than 30 references to Peter in Rome. Among these, we read:
"You [Pope Soter] have also, by your very admonition, brought together the planting that was made by Peter and Paul at Rome and at Corinth; for both of them alike planted in our Corinth and taught us; and both alike, teaching similarly in Italy, suffered martyrdom at the same time" (Letter to Pope Soter [A.D. 170], in Eusebius, History of the Church 2:25:8).
Dionysius of Corinth
"Matthew also issued among the Hebrews a written Gospel in their own language, while Peter and Paul were evangelizing in Rome and laying the foundation of the Church" (Against Heresies, 3, 1:1 [A.D. 189]).
Irenaeus
"It is recorded that Paul was beheaded in Rome itself, and Peter, likewise, was crucified, during the reign [of the Emperor Nero]. The account is confirmed by the names of Peter and Paul over the cemeteries there, which remain to the present time. And it is confirmed also by a stalwart man of the Church, Gaius by name, who lived in the time of Zephyrinus, bishop of Rome. This Gaius, in a written disputation with Proclus, the leader of the sect of Cataphrygians, says this of the places in which the remains of the aforementioned apostles were deposited: ‘I can point out the trophies of the apostles. For if you are willing to go to the Vatican or to the Ostian Way, you will find the trophies of those who founded this Church’" (Disputation with Proclus [A.D. 198] in Eusebius, Church History 2:25:5).
Gaius
As you can see, Rokke, I am much too detail oriented. Cronos will undoubtedly respond in a much simpler way. Alas, the heart that holds strong to faith and wishes to impart it to seekers, is limited by a lack of formalized education in theology. I can only point; the rest is up to you and God. Place your trust in Him and ask our Lord for His guidance. I am but a lowly servant.
A Blessed Thanksgiving to you and your family!
Happy Thanksgiving.