Personalism, understood as the perception of mankind as a psychophysical unity (made of soul and body intrinsically connected) rather than a philosophical concept developed since the early days of Christianity, frequently reconsidered as such in recent times, is a practice which dates back to the early periods of Christianity, which precedes the observations of the Church founding Fathers.

In this article, the aim is to retrace the early stages of this phenomenon so to highlight how gradually the ancient society turned into a medieval civilization, which, from a legal point of view, is not to be considered as a step backwards.  

Firstly, we will consider the Acts of the Apostles and the Letters of St. Paul, continuing until the formation of the feudal society.

In the Acts of the Apostles, it is stressed that the early Christians on a voluntary basis gathered all their property and practiced among them the fractio panis (breaking of the bread), which represents the Eucharist. Subsequently, the canteen services, namely solidarity for the poor, was entrusted to the deacons while the spreading of the word was reserved to the Apostles. In brief, equality between brothers was nothing but a solidarity praxis. However, in Paul's letter to Philemon devoted were asked to welcome the slave Onesimus as a brother and that can be interpreted as the first conceptualization of the overcoming of slavery.

On the other hand, it has to be noticed that in the first Century, simultaneously with the development of Christianity, slavery was waning to the point that in the time of Emperor Claudius several freedmen, that is to say freed slaves, were able to access to higher positions.

Having said that, let us focus on personalism as a concept. It was conceived in a theological ambit with Tertullian who wrote Contro Prassea (Against Praxis), in which he claims that Father, Son and Holy Spirit are three persons and not three aspects of a single God. Tertullian does not own  the concept of the Trinity yet, so he subordinates the Son to the Father and the Holy Spirit to both Father and Son, but he introduces a concept that will have an impact on the anthropological level: Jesus is both God and man. Jesus is the same person (prosopon) with two natures, unlike us: people with only one nature. It will be, in fact, Boethius (480-526) in his "Liber de persona" to give a definition of the person as an individual substance of a rational nature with the purpose of rejecting the heresies of Eutyches (Monophysitism) and Nestor, who saw in Christ two natures: divine and human.

Alongside, the historical reality of the time changed. It undermined both the slavery companies (as keeping a slave was too expensive) and the free properties (mainly because of taxes). The practice of serfdom - imposed by law on freeholders by Diocletian, or practiced by the landowners so to get rid of slaves- became very common. However, a servant had the right to have a family of his own and was no longer a commodity that could be sold (the land sale was possible along with the servants). In other words, the servant acquired dignity as a person with rights on his wife and children.

Meanwhile, the barbarian invasions were changing the ethnic composition of the ancient world in the western part of the Empire. In City of God, St. Augustine will claim that the right opposition is between believers and misbelievers, not between Romans and Barbarians. Briefly, once converted, also the Barbarians belonged to the City of God and they had to be considered as brothers. After the slaves, Christianity recognized equal dignity to the Barbarians.

As one can see, there were various conceptual and historical steps that for a while run parallel, but then they converged into a society: the feudal society of high Middle Age. It was a society where everyone had personal dignity (body and soul unity), but there also was a hierarchical pyramidal structure that weakened the principles. For the lower classes, life was tough and the only way out seemed to service for a monastery in exchange for protection. Notwithstanding, even nowadays, this historical contradictions between principles and reality have always existed.