Daniel answered...

When Jesus was on the earth he established his church. To guide it, 12 apostles were called by God and had priesthood authority to act in his name. When an apostle died, he was to be replaced so that there would always be 12 “special witnesses” of Christ (this is shown by the calling of Mathias as a member of the 12 in Acts:1)
The early years were troublesome times for Christians. The greatest antagonist to the church was the Roman Empire. During this era of persecution, apostles were killed and priesthood authority was lost. Centuries after Christ was crucified Rome pulled a 180 and adopted its own form of “Christianity” as the mandated state religion. To conform to previously held pagan traditions, ordinances like baptism were changed and creeds of faith, not found in the bible, were established.
Recognizing the discrepancies between this church and New Testament Christianity, righteous people protested and many of their followers formed new churches. This era of protestant reformation was critical in advancing religious liberty. But simply recognizing the errors of a church, does not give one God's priesthood authority (see Hebrews 5:4) Even those with the best intentions of following Christ’s teachings need proper priesthood authority to be baptized. The world needed a Restoration of Christ’s original church, not a reformation of an apostate version of it. And as soon as a nation was established with the religious freedom to allow it, the Lord did restore his church!