What two decisions did constantine make that changed european history?

constantine changed european history by giving christianity legal standing: he changed the way the public looked at christianity and turned it into an accepted religion. he ended the persecution of christians and actually established it as the official religion of the land. constantine also moved the capital from Rome to byzantium, which was renamed constantinople. establishing constantinople eventually split the roman empire in two, eastern and western halves. This division eventually lead to the fall of the roman empire, with the western half of the roman empire falling about 1000 years before the eastern half.