A mistake of Roderic of Toledo, in comparing the lunar years of the Hegira with the Julian years of the Era, has determined Baronius Mariana, and the crowd of Spanish historians to place the first invasion in the year 713, and the battle of Xeres in November, 714. This anachronism of three years has been detected by the more correct industry of modern chronologists, above all, of Pagi (Critica, tom. iii. p. 169, 171-174), who have restored the genuine date of the revolution. At the present time an Arabian scholar, like Cardonne, who adopts the ancient error (tom. i. p. 75), is inexcusably ignorant or careless.