When did doubts regarding the apostolic authorship of the Fourth Gospel first arise in the history of modern biblical criticism? In the case of the Fourth Gospel, the Gospel’s own claims to have been written by one of Jesus’ own disciples and patristic attribution to the apostle John held the day, with very few exceptions, until the rise of historical criticism in the seventeenth and eighteenth centuries. From the standpoint of contemporary scholarship, which has largely abandoned the traditional view of the apostolic authorship of the Fourth Gospel, the question arises what sparked this “paradigm shift,” and how it came about. This article focuses especially on the last decade of the eighteenth century when doubts regarding the Fourth Gospel’s authorship crystallized that would cast their early shadows on the debate which has continued until this day. The hope is that, by studying the genesis of those early doubts, we may gain a better understanding of both early historical criticism and contemporary scholarship, especially with regard to the Fourth Gospel’s authorship.