He was the first recorded person to refer to the Christian Church as "Catholic." Some time before the year 107, St. Ignatius wrote,
Where there is Christ Jesus, there is the Catholic Church.The word "Catholic" comes from the Greek word katholikos which means "universal". The church, the Christian church, was the Catholic Church in the time right after the apostles.
All the Christian Churches, whether in Jerusalem, Rome or elsewhere were all part of the One Church founded by our Saviour Jesus Christ. That one Church was "Catholic"--Universal--and still takes its teachings directly from the Apostles--the men who were hand picked by Christ while He walked on the earth.
Jesus gave Peter the "keys to the kingdom of Heaven" and gave him (and the men he ordained by the laying on of hands) the "power to bind and loose." (Matthew 16: 19) That power exists today, as it did in the first century, in the Catholic Church.
Its members, men, women, lay and religious, lowly and leaders are far from perfect. Many are not even "good". But, Jesus promised that
You are Peter, and upon this rock I will build my church, and the gates of the netherworld shall not prevail against it. ~Matthew 16:19That is a promise that St. Ignatius believed in, in the years that the first Apostles still walked and taught.