Hegesippus, a historian of the period immediately following apostolic times, is quoted by Eusebius in his Ecclesiastical History, 3.32 as saying:
Besides this, the same man, when relating the
events of these times, adds that until then the Church had remained a pure and
undefiled virgin, since those who attempted to corrupt the sound rule of the
Saviour’s preaching, if any did exist, until then lurked somewhere in obscure
darkness. But when the sacred band of the Apostles had received an end of life
in various ways, and that generation of those who were deemed worthy to hear
the divine wisdom with their own ears had passed away, then the league of godless
error took its beginnings because of the deceit of heretical teachers who,
since none of the Apostles still remained, attempted henceforth barefacedly to
proclaim in opposition to the preaching of truth ‘the knowledge falsely
so-called.’ (Eusebius of Caesarea, Ecclesiastical History, Books 1-5
[trans. Roy Joseph Deferrari; The Fathers of the Church 19; Washington D.C.:
The Catholic University of America Press, 1953], 192)