In principio erat uerbum et uerbum erat apud deum et dens erat uerbum. hoc erat in principio apud deum· omnia per ipsum facta sunt· et sine ipso factum est nihil· quod factum est in ipso uita erat· et uita erat lux hominum· et lux in tenebris lucet· et tenebrae eam non conprehenderunt (= John 1.1-5).
The text itself is, as has been mentioned, almost pure Vulgate. Fuldensis begins, then, with the Lucan preface and then part of the Johannine preface. What comes next is about Zacharias the priest.
Compare this introduction to that of the Arabic Diatessaron:
And what comes next is about Zacharias the priest. So Fuldensis includes the Lucan preface, while the Arabic Diatessaron excludes it. Was the preface original to this Diatessaronic text, and the Arabic removed it, or was it originally absent, and the Latin added it? An important clue comes from the capitularium (list of chapters) that stands before the text:
II. de sacerdotium zacchariae
The list of chapters includes the Johannine preface followed by the story of Zacharias the priest; the Lucan preface is not there. The natural supposition is that the Lucan preface has been added to a text whose list of chapters was not correspondingly altered. There are other clues from the chapter titles, as well. For example, chapter X is entitled ubi herodes interfecit pueros ("when Herod murdered the children"), but the Vulgate text of Fuldensis says that Herod "killed" (occidit) the children, suggesting that the chapter titles belong to a text that is not Vulgate.