According to the Catechism of the Catholic Church, the Apostles’ Creed is the oldest Roman catechism and carries it’s authority from the chair of the foremost apostle, Peter: “The Apostles’ Creed is so called because it is rightly considered to be a faithful summary of the apostles’ faith. It is the ancient baptismal symbol of the Church of Rome. Its great authority arises from this fact: it is ‘the Creed of the Roman Church, the See of Peter, the first of the apostles, to which he brought the common faith” (CCC, 194).
The Apostles’ Creed is also Trinitarian, beginning with the first Person of the Trinity, God the Father, moving to the redemption of mankind through the second Person of the Trinity, Jesus Christ, and then to the work of the third Person of the Trinity, the Holy Spirit. Therefore the Apostles’ Creed is also a baptismal seal: the profession of faith to which we are entrusted on the day of our baptism
“This Creed is the spiritual seal, our heart’s meditation and an ever-present guardian; it is, unquestionably,the treasure of our soul.” – Saint Ambrose