These is simply the historical Catholic Church based in Rome.

Roman (or Latin) Rite Catholics believe that their church is the true and legitimate linear descendant of the original Christians. The Popes form and unbroken line of succession from the time of Peter; the Protestants and other Christians (such as the Anglicans) broke away from the Church of Rome and, likewise, the Greek Orthodox (schismatics) also broke away from the authority of Rome. It's an oversimplification, but that's the essence of it.