Catholicism began in 33 AD. Jesus made Simon the foundation of his Church - changing his name to Kephas (Peter), which literally means "rock" - thus beginning something which I am proudly part of today. Peter was the first head of this new church, as he is the spokesperson of the apostles, the first to enter the empty tomb, and always listed first in the Bible. At Pentecost, he and the apostles were given the fire and ability to spread Jesus's message all over the world. All of the apostles were teachers and they taught their followers the true words of Jesus: His words on the mountain, His words at the last supper, His words on the cross - and His words to them individually, as a group, or even just overheard. Jesus's words and traditions were repeated everywhere the apostles and their followers went. Many were written down, some were just retold and re-enacted. Those that were written down were gathered a few hundred years later and put together by other Catholics to become our New Testament. Peter's successor, one of his students and followers, was the next one to hold the keys to the kingdom.
Peter was crucified in Rome and is buried right where St. Peter's Basilica is. After Peter's (and Paul's) death in around 64 AD, a Roman named Linus was his successor. There is an unbroken line of Peter's successors that still continues after 2000 years. We call these men the fathers of our church - originally "pappas" (in Greek), from which we get the word "pope". Here is a list: https://en.wikipedia.org/wiki/List_of_popes#Chronological_list_of_popes
Every day at our beautiful Catholic mass, we do what the apostles and their successors did with their followers from right after Pentecost: we profess our faith and praise in Jesus, read and reflect on the Holy words of Jesus, the adventures and letters of the apostles who followed Him, and the words of the ancient scriptures Jesus followed, and we recreate the words and actions of Jesus at his last supper with the apostles before his crucifixion. Every Catholic mass everywhere in the world read the same readings on any given day and say the same words in whatever language they are speaking. Jesus is there with us at every mass and is the bread and wine we receive - just as He said He would be. "Recalling these words of Jesus, the Catholic Church professes that, in the celebration of the Eucharist, bread and wine become the Body and Blood of Jesus Christ through the power of the Holy Spirit and the instrumentality of the priest. Jesus said: "I am the living bread that came down from heaven; whoever eats this bread will live forever, and the bread that I will give is my flesh for the life of the world. . . . For my flesh is true food, and my blood is true drink" (Jn 6:51-55). The whole Christ is truly present, body, blood, soul, and divinity, under the appearances of bread and wine—the glorified Christ who rose from the dead after dying for our sins. This is what the Church means when she speaks of the "Real Presence" of Christ in the Eucharist." (usccb).
Clement of Rome's letters (or "epistles") were widely read in the Early Church. His was the earliest epistle from a Church Father outside the New Testament. Clement was consecrated by Peter and was said to be a leading member of the church in Rome in the late 1st century.
Ignatius of Antioch was a student of the apostle John. Before he was martyred in Rome, he wrote letters which included the topics of ecclesiology (the study of Christianity's leadership, polity, discipline, & destiny), the sacraments, the role of bishops, and the incarnation of Christ.
Polycarp of Smyrna was another student of the apostle John and was a Christian bishop in Smyrna (now Turkey). He is among the earliest Christians whose writings survived. He authenticated a lot of Christian teachings through his connection with the apostle John. He condemned any heresy.In like manner also the chalice, after He had supped, saying: This chalice is the new testament in My Blood: this do ye, as often as you shall drink, for the commemoration of Me. For as often as you shall eat this Bread, and drink the Chalice, you shall show the death of the Lord, until He come.
Therefore whosoever shall eat this Bread, or drink the Chalice of the Lord unworthily, shall be guilty of the Body and of the Blood of the Lord. [1 Cor: 11: 23-27]
These are the words said in our mass today. It identifies the Eucharist with the Passion. We have been commanded to celebrate the Eucharist in Jesus's memory. And the Catholic Church has done that unceasingly for 2000 years.