Yeah, my understanding is that truce didn’t last too long after Constantine died. Here’s part of a paper I wrote about this awhile ago:
The Religion of Ancient Rome had great influence from Greek traditions, such as the legacy of the famous Eleusinian Rites. It is a common misconception by modern scholars that the purpose of these rites was to provide assurance of immortality for participants. The truth is that immortality was already considered to be a surety for everyone, the ceremonies were meant only to ensure greater bliss in the afterlife. The purification process of body and soul began with a baptism in the sea, as well as a fast and focused meditation. Mysterious and complex process of initiation are unknown, but are said to have changed the lives of initiates forever.
Historical archaeology has uncovered little evidence of Archaic Roman Religion before the second century B.C. There are a few epigraphical texts from this time, but they are difficult to decipher, and there is little else besides these to reference. Literary records before the time of the Etruscans is very limited, fragmented, and confused. The most reliable source of information known by scholars today is the Pre-Julian Calendar. This record is a reconstruction from fragments of approximately 20 copies of the document. Credited as the calendar of King Numa’s original authority, it was maintained by the rule of Julius Ceaser, who made limited changes such as adding ten days to the year. This calendar was based on an eight-day week.
Roman religion was primarily grounded in agricultural observances in regards to the weather, without mythologies or temples. Some scholars consider this to be a “pre-deistic” age of religion, that is a religion without Gods, but it is known that Mars and Jupiter were acknowledged as Gods during this time. These gods were perhaps still not considered of paramount importance in the structure of the religion, which was based instead in “Numina”; mysterious powers that controlled the forces of nature.
Georges Dumezil, one of the most influential French Scholars of the twentieth century, has published a large volume titled Archaic Roman Religion, but this must be conservatively considered as most of the research that this document is based in is from the last two centuries of the Roman Republic. Dumezil was a clever scholar and provided valuable insight in his perspective about the timeless structures of religions associated with Indo-European languages. The model of study developed by Dumezil is helpful in considering the details of ancient traditions. His method was to apply a microscopic and comprehensive analysis of all available evidence, in a manner that can be in a large part credited to the influence of French anthropologists Marcel Mauss and Granet.
The only dogma of Archaic Roman Religion was proper participation in traditional ritual ceremonies, called orthopraxis. There was freedom of belief for all citizens, who were welcome to express their beliefs openly. No teaching or initiation was required for the religion; duties were defined by one’s status as a Roman citizen. It was a religious tradition set in the structure of community, not for individual salvation. There were many different denominations within the city of Rome, each based in a particular social group, such as units of the legion and colleges of the city. There was no moral or ethical code of the religion separate from the non-religious traditions of Roman life.
The principal purpose of the religion was to provide for the wellness of the living mortal community; it was not focused on the transition to the afterlife. The gods oversaw the community for the people, not the people for the community. Religion was directly linked to the politics of the city; there was no division between these aspects of their culture. There was no individual authority over the religion; the community shared power. There was a polytheistic belief structure, with gods considered to be members of the same community as mortals.
This essential structure was common for many ancient cites in Greece and Italy. This came from the ideology of original cites of the Mediterranean since the 8th century B.C. The liberty of citizens was of paramount consideration for the ideology, seen as more important even than relation with the gods. The identity of gods was founded on reason rather than fear.
Over the course of the Roman Empire’s expansion, the concept of the ideal Mediterranean city began to shift. With this shift, the structure of religion was also altered. While it had once been the long-standing belief that relations between citizens and the gods were considered within the same light as community relations amidst citizens, this began to change. Liberty of citizens lost its place as the principal concern of religion, and in its stead was placed submission to authority. This change developed gradually, and it was not until the third century A.D. that it became common and widespread in the Roman Empire. Some individuals and groups considered themselves to wield absolute authority over their gods, and the people subjugated by their rule. This created division and resentment within the empire, which contributed to its eventual dissolution.
Constantine the Great, the first Christian emperor of the Roman Empire, sought to prevent a civil war amongst his people by dividing the empire amidst his sons and nephews. Restoration of the monarchy had been a primary mission of Constantine during his life, as well as the pursuit of creating unity of faith within the empire. When this failed, he resorted to drastic measures in a vain attempt to prevent war. England, France, and Spain were trusted to the rule of his eldest son, Constantine the second. Egypt, Syria, and Asia Minor were to be ruled by his second son, Constantius. His youngest son, Constans, was gifted the rule of North Africa, Italy, Illyricum, and Thrace, including power over Rome and Constantinople. Armenia, Macedonia, and Greece were given to two of Constantine’s nephews, but the army rejected their authority, as they had respect only for the authority of the sons of their emperor, not his nephews.
Civil war broke out between Constantine II and Constans, while Constantius traveled to Constantinople to reign over this city with outrageous incompetence. All of Constantine’s male relatives other than his sons and two nephews Julian and Gallus were murdered. Constantius re- kindled the ancient conflict with Persia that had smoldered ever since the battle of Marathon.
Reference Authors: Frederick Grant, John Scheid, and Will Durant.