We just learned about the Neume.
Another part of early Christianity is the Christianization of Poland.
In 966 AD the ruler of Poland named Mieszko I was baptized.
When he got married to Dobrawa of Bohemia, she helped him become a Christian, and then after he was baptized many people across all of Poland learned about Jesus and decided to become Christians.
(from: wikipedia - christianization of poland)
Kid Facts - Blast from the past: Ignatius of Antioch