The first glimmerings of this history-legend refer to an unknown country "in the north." About the middle of the third century of the Christian era there proceeded thence the people known as the Mayas, who traversed Mexico and arrived in Yucatan; and they are the reputed originators of the singular and beautiful temples encountered there, and the teachers of the stone-shaping art whose results arouse the admiration of the archaeologist and traveller of to-day, in that part of Mexico. The descendants of the Mayas are among the most intelligent of the native tribes inhabiting the Republic, doubtless due to the influence of the polity and work of their ancestors. Time went on. About the middle of the sixth century A.D. another people came "out of the north"--the famous Toltecs, and in their southward migration they founded successive cities, ultimately remaining at Tollan, or Tula, and to them are attributed the remarkable pyramids of Teotihuacan, Cholula, and other structures. Tula is some fifty miles to the north of the modern city of Mexico, and it formed the centre of the powerful empire and civilisation of this cultured people. Eleven monarchs reigned, but the Toltec Empire was overthrown; the people dispersed, and they mysteriously disappeared at the beginning of the twelfth century A.D., after some 450 years of existence. None of these dates, however, can be looked upon as really belonging to the realm of exact history. [Illustration: PREHISTORIC MEXICO: TOLTEC PYRAMID OR TEOCALLI OF THE SUN AT SAN JUAN, TEOTIHUACAN. (Exploration and restoration work being carried on.)]