Up to December 18, 1763, Gibbon was evidently a believer.
In an entry in his private journal under that date he speaks of a Communion Sunday at Lausanne as affording an "edifying spectacle," on the ground that there is "neither business nor parties, and they interdict even whist" on that day.

How soon after this his opinions began to change, it is impossible to say.

But we are conscious of a markedly different tone in the _Observations_, and a sneer at "the ancient alliance between the avarice of the priests and the credulity of the people" is in the familiar style of the Deists from Toland to Chubb.

There is no evidence of his familiarity with the widely diffused works of the freethinkers, and as far as I am aware he does not quote or refer to them even once.

But they could hardly have escaped his notice.