Photo by Anthony Majanlahti; Source: Wikipedia
Licinius married Constantine’s half-sister, Constantia, and the two of them formed a united front against the ambitions of Maximin Daia. Licinius was able to defeat him near Hadrinoupolis in Thrace, assuming control of the entire Eastern empire. There was now relative stability, but not harmony. Constantine and Licinius argued constantly. Licinius began persecuting Christians again in 320, eventually leading to Constantine’s invasion of his territory in 323.
After his victory over Licinius, Constantine became sole emperor of Rome and proceeded to further the interests of Christianity. In 324, for example, he exempted Christian clergy from all obligations otherwise imposed upon citizens (like taxation). At the same time, less and less tolerance was bestowed on pagan religious practices.
The above photo is of a huge bronze head of Constantine — about five times life-size, in fact. The first emperor in at least two centuries to be depicted without a beard, his head originally sat atop a colossal statue that stood in the Basilica of Constantine.
This image probably comes from late in his life and, as was characteristic of depictions of him, shows him gazing upward. Some interpret this as suggesting Christian piety while others argue that it’s simply characteristic of his aloofness from the rest of the Roman people.