In what areas was the Catholic church dominant in the lives of people during this time?

The history of the Catholic Church begins with the teachings of Jesus Christ, who lived in the 1st century CE in the province of Judea of the Roman Empire. The contemporary Catholic Church says that it is the continuation of the early Christian community established by Jesus.

Christianity spread throughout the early Roman Empire despite persecutions due to conflicts with the pagan state religion. In 313, the struggles of the early church were lessened by the legalization of Christianity by the Emperor Constantine I. In 380, under Emperor Theodosius I, Christianity became the state religion of the Roman Empire by the decree of the emperor, which would persist until the fall of the Western Empire, and later with the Eastern Roman Empire until the fall of Constantinople.

because of the war the westeners befriended japan and each other advance.