There is little room for doubt that the remains of ancient roads or causeways still to be seen in Yucatan are, so far as the history of the peninsula is concerned, of considerable antiquity. Two of the earliest and most important historians of Yucatan, namely, Diego de Landa and Bernardo de Lizana, mention them, and brief notices of their existence have been made by explorers in the nineteenth century. It seems highly probable that as early as a thousand years ago a broad highway extended a considerable distance across the northern part of the peninsula of Yucatan, if indeed it did not reach from the eastern to the western shores of the country.