Gospel Recovery at the Reformation

What was recovered at the Protestant Reformation in the 16th century. The short but accurate answer is, The Gospel! Now the gospel is the announcement of the person of Jesus Christ and what he accomplished for us people and our salvation.
It is the good news of salvation from sin and its consequences to eternal life in fellowship with the holy God through the actions of Jesus- lI delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, 4 that he was buried, that he was raised on the third day in accordance with the Scriptures, and that he appeared to Cephas, then to the twelve. 6 Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep. 7 Then he appeared to James, then to all the apostles. 8 Last of all, as to one untimely born, he appeared also to me....He presented himself alive to them after his suffering by many proofs, appearing to them during forty days and speaking about the kingdom of God.
1 Corinthians 15:1-8; Acts 1:3 He presented himself alive to them after his suffering by many proofs, appearing to them during forty days and speaking about the kingdom of God.

The recovery of the gospel is summed up in the slogan- Christ Alone
Acts 4:12 And there is salvation in no one else, for there is no other name under heaven given among men[a] by which we must be saved."
John 14:6 "I am the way, and the truth, and the life. No one comes to the Father except through me.