“But,” he adds, “finding Tacitus, Eumenius, Ammianus Marcellinus, and Beda, in full and direct opposition to this idea, [certainly false with respect to the first and two last, if not to the second;] and not choosing to imitate our Scotish antiquitists in fighting against authorities,[which is nevertheless his constant practice,] I was forced to abandon this ground. … For ancient authorities,” he concludes, “are the sole guides to real truth in historic antiquities; conjectures and arguments are only ingenious lies:” which made him abandon the former, and have recourse only to the latter (I. 106).
Source: wiktionary