Only a few in Paul's audience in Athens, the source of this coin, believed the Good News about what Jesus has done for us. The people were very religious, worshiping a large number of gods and following many different doctrines. Paul told them that they needed to worship the God whom they did not know, the One who created everything. Most of them could not accept the declaration that God raised Jesus from the dead after his willing sacrifice of himself for our sins. Those who did believe enjoyed God's gift of eternal life thereafter.
[not in SG; Zeus and Athena; A - TH - E for Athens]
or general topics:
Birth of Jesus,
Other Gospel topics,
Book of Acts,