What is the oldest Christian sect?

Nearly all Chrsitians today believe that the Christian sect that led eventually to the Coptic Church and then, following the Great Schism, to the Roman Catholic and Orthodox Churches was the first Christian sect. However, there is good evidence that Christianity was already split into competing sects from the earliest times, with the apostle Paul complaining about those who taught a "different Christ". Since success has consistently gone to the group that has won the political battles, all we know about the predecessor to the Roman Catholic and Orthodox Churches is that it was the most successful. We can not be sure which was the first Christian sect. Perhaps the Coptic Church is the oldest extant denomination that has survived unchanged since its inception.