Where was the new capital under constantine and how did he view christianity?

Constantine moved the capital of Rome to Constantinople in 330 BCE.
His views on Christianity were supportive, in fact he issued the Edict of Milan in 313 BCE making Christianity legal in Rome. He also called the Council of Nicaea in 325 BCE, inviting all of the bishops of the church, and this became the first general council in the history of the Christian Church.