Volumes have been written giving detailed analyses of the extraordinary things that occurred in the first thousand years of church history, events that influenced everything that came after them. In this brief overview, I’m going to look at five dimensions of activity that had monumental impact for the future history of Christianity.
The first such matter was the rise of the so-called “mono-episcopacy.” By the end of the first century, it was seen that the bishop of Rome had grown exceedingly more influential than other bishops of that period. Within the next century or so, the authority and power of the bishop of Rome was consolidated for all future history of the Roman Catholic Church. The singular authority that became located in the bishop of Rome gave the church a unifying base. The influence of the pope in the first thousand years of the church is almost impossible to measure.
In that light, we see the second major impact come to the fore — the innovations brought to Christianity by perhaps the most important pope of the first millennium: Gregory the Great. In his activities he consolidated the power vested in the sacraments of the church and spawned the vast sacerdotal system (priests through ordination receiving the ability to act as mediators of God’s grace to man through the sacraments) with which all future Catholicism would be associated.
A third element that had great influence on the future of Christianity was the rise of the monastic movement. Beginning with the extreme asceticism of people such as Anthony of the Desert (ca. 251–356), this radical brand of self-denial became institutionalized with the rise of various monastic orders, most of which exist to this day. These orders include the Benedictines, the Augustinians, the Franciscans, and others that date back several centuries.
Perhaps most important in the first thousand years were the ecumenical councils. Of the several ecumenical councils, clearly the two most important were those that were convened in the fourth and in the fifth centuries. The fourth century saw the convening of the Council of Nicaea and the production of the historic Nicene Creed. Here the church gave its definition of the deity of Christ over against the heretic Arius, who argued that though Jesus was the first creature created by God and in that sense the firstborn of God, He nevertheless remained a creature and so was not to be worshiped as the second person of the Trinity.
The tension that was provoked by the Arian controversy and the years of deliberation and discussion that ensued finally culminated in the Council of Nicaea in 325. In that council the full deity of Christ was affirmed, and Christ, the divine Logos, the second person of the Trinity, was declared to be co-essential and co-eternal with the Father. This formula gave the church a way to distinguish among the persons of the Godhead, while at the same time attributing a singular divine essence to the three. The antitrinitarian Christology of Arius saw the beginning of its defeat with this ecumenical council.
The fifth century saw the convening of perhaps the most important christological council in all of church history at Chalcedon in 451. Here orthodox Christianity had to fight a battle on two fronts. On the one hand was the opposition to the orthodox view of the nature of Christ in His incarnation by Eutyches. Eutyches was a monophysite — he declared that Jesus had only one nature. This nature was called a single “theanthropic nature,” meaning a divinely human nature or a humanly divine nature. This position, saying that Christ had one nature (Greek: monophysis), obscured both the real deity and the real humanity that were united in the incarnation of Christ.
On the other side of the debate, the Nestorians argued that if Jesus had two natures, He had to have had two persons as well, so they separated the two natures of Christ into two persons. Over against both heresies, Chalcedon gave its famous formula by which it declared that Christ is truly God and truly man, with the natures perfectly united in such a way that they are not confused — the natures are without mixture, confusion, division, or separation; each nature retains its own attributes. This was a watershed council because it set the boundaries or parameters of christological speculation. The two natures were not to be merged or confused; the human nature, for example, would not be absorbed or swallowed up in the divine nature and vice versa. At the same time, the two natures were not to be separated so as to lose their unity in the one person.
Throughout history since Chalcedon, the church in virtually every generation has had to face the tendencies of either confusing the two natures or dividing or separating the two natures. Orthodoxy in the fifth century declared that the natures must be distinguished yet never separated. They must be distinguished and never be co-mingled.
The other noteworthy event of the first millennium was the extraordinary impact of Augustine of Hippo, perhaps the greatest theologian of that millennium. Augustine was called to defend the church against the heresies of the Donatists in their disputes about baptism and, more importantly, against the heretical views of Pelagius, who denied original sin, arguing that even apart from grace the descendents of Adam could achieve lives of perfection. Augustine’s theology of salvation shaped the future history of Christianity, particularly as it helped quicken Luther and Calvin for the Protestant Reformation. At the same time, Augustine’s view of the church solidified the power of the monoepiscopacy and the Roman magisterium for all future generations.
These five aspects of the first millennium are only illustrative of a vast number of things that in the providence of God developed over this period of time. Sadly, at the end of this millennium, the church was already groping in the darkness and biblical soteriology had declined to such a degree that the gospel was rapidly becoming obscured, even becoming almost totally eclipsed until it was recovered in the sixteenth century Reformation.