4. For our fourth certainty we resort to the time when the history of the Church returns once more to the full light of day, in the last quarter of the second century. Then we find two things quite clearly established, which have continued in Christendom from that day to this. We find a _regularly organized clergy_, not only distinctly marked off from the laity, but distinctly _marked off among themselves by well defined gradations of rank_. And, secondly, we find that _each local Church is constitutionally governed by one chief officer_, whose powers are large and seldom resisted, and _who universally receives the title of bishop_. To these two points we may add a third. There is no trace of any belief, or even suspicion, that the constitution of these local Churches had ever been anything else. On the contrary, the evidence (and it is considerable) points to the conclusion that Christians in the latter part of the second century--say A.D. 180 to 200--were fully persuaded that the episcopal form of government had prevailed in the different Churches from the Apostles' time to their own. Just as in the case of the Gospels, Irenæus and his contemporaries not only do not know of either more or less than the four which have come down to us, but cannot conceive of there ever being either more or less than these four: so in the case of Church Government, they not only represent episcopacy as everywhere prevalent in their time, but they have no idea that at any previous time any other form of government prevailed. And although Irenæus, like St. Paul and Clement of Rome, sometimes speaks of bishops under the title of presbyter, yet it is quite clear that there were at that time presbyters who were not bishops and who did not possess episcopal authority. Irenæus himself was such a presbyter, until the martyrdom of Pothinus in the persecution of A.D. 177 created a vacancy in the see of Lyons, which Irenæus was then called upon to fill; and he held the see for upwards of twenty years, from about A.D. 180 to 202. From Irenæus and from his contemporary Dionysius, Bishop of Corinth, we learn not only the fact that episcopacy prevailed everywhere, but, in not a few cases, the name of the existing bishop; and in some cases the names of their predecessors are given up to the times of the Apostles. Thus, in the case of the Church of Rome, Linus the first bishop is connected with "the two most glorious Apostles Peter and Paul": and, in the case of Athens, Dionysius the Areopagite is said to have been appointed first bishop of that Church by the Apostle Paul. This may or may not be correct: but at least it shows that in the time of Irenæus and Dionysius of Corinth episcopacy was not only recognized as the universal form of Church government, but was also believed to have prevailed in the principal Churches from the very earliest times.[47]