Were Some People Really Worshipping "Unknown Gods" in the Roman Empire?

A First Century Altar "To the Unknown Gods" Found at Pergamum

In Acts 17:22-31 the apostle Paul is in Athens.  Here's what happens:

 So Paul, standing in the midst of the Areopagus, said: “Men of Athens, I perceive that in every way you are very religious.  For as I passed along and observed the objects of your worship, I found also an altar with this inscription: ‘To the unknown god.’ What therefore you worship as unknown, this I proclaim to you.  The God who made the world and everything in it, being Lord of heaven and earth, does not live in temples made by man, nor is he served by human hands, as though he needed anything, since he himself gives to all mankind life and breath and everything. And he made from one man every nation of mankind to live on all the face of the earth, having determined allotted periods and the boundaries of their dwelling place, that they should seek God, and perhaps feel their way toward him and find him. Yet he is actually not far from each one of us, for

“‘In him we live and move and have our being’;
as even some of your own poets have said,
“‘For we are indeed his offspring.’

Being then God's offspring, we ought not to think that the divine being is like gold or silver or stone, an image formed by the art and imagination of man. The times of ignorance God overlooked, but now he commands all people everywhere to repent, because he has fixed a day on which he will judge the world in righteousness by a man whom he has appointed; and of this he has given assurance to all by raising him from the dead.”

A question many people could ask would be, "Did any people really worship at altars to unknown gods in the first century Roman empire???"  This artifact, discovered in 1909 speaks directly to that question.

George Aaron Barton explains:

In the year 1909 an altar was discovered in the sacred precinct and temple of Demeter at Pergamum in Asia Minor, the home of one of the seven churches in the book of Revelation (Rev. 2:12), which bore a mutilated inscription. This inscription in the judgment of several impartial epigraphists should be restored as follows: To unknown gods, Capito, torch-bearer.

This inscription shows people were creating altars to unknown gods in the first century throughout the Roman empire.