The three grand divisions in the history of the Christian Church, with their subdivisions or periods, are as follows:--
I. THE EARLY CHURCH.
1. From Pentecost to Constantine (30-313).
2. From Constantine to Gregory the Great (313-590).
II. THE MEDIÆVAL CHURCH.
1. From Gregory the Great to Gregory VII. (590-1073).
2. From Gregory VII. to Boniface VIII. (1073-1294).
3. From Boniface VIII. to the Reformation (1294-1517).
III. THE MODERN CHURCH.
1. From the Reformation to the Peace of Westphalia (1517-1648).
2. From the Peace of Westphalia to 1120.
3. From 1720 to the present.
It is possible that in one or two instances equal convenience might have been realized by drawing the dividing line at a different point. Still, it will not be difficult to find a reason for each item in the scheme adopted. The decree of toleration published by Constantine in 313 marked such a decisive change in the fortunes of Christianity that the first period is properly made to end at this date. Before the end of the sixth century the repeated incursions of the barbarian tribes had largely overthrown the old civilization in the West. At the same time, moreover, the Church, in the tenor of its worship and life, had advanced far toward the phases which were dominant in the Middle Ages. It is obviously suggested, therefore, that the pontificate of Gregory the Great should be allowed to introduce the history of the Medieval Church. In passing through the intervening centuries to the Reformation, we naturally make a threefold division, since the mediaeval order of things had its formative period, its period of culmination, and its period of decline or incipient disintegration. The Peace of Westphalia was of profound significance as respects the relation of Roman Catholic and Protestant powers upon the Continent. It happened also that England witnessed a great crisis near the date of this famous settlement. The year 1648, therefore, is fixed upon as ending the first period of the Modern Church. A second period of modern history is made to end at 1720, not because that specific year was marked by any event of signal importance, but because about this time an era of criticism, an era of decided tendencies toward new departures, was inaugurated. The interval between 1720 and the present might be subdivided. However, as it will be convenient, in consideration of the complexity of the more recent history, to consider the leading countries by themselves, the divisions may be made for the different nations according to their most noted epochs.