“All writers concur in stating that the market was held on each fifth day, when all adults were obliged by law to resort to the appointed market-place. The entire produce and manufacture of the state were brought there, even from great distances, severe penalties being incurred by those who bartered the products of agriculture or manual labor on the highway or elsewhere. On the broad, straight, cemented roads which led from the four quarters to the heart of the capital, ‘resting places’ for the wayfarers and carriers were provided at fixed intervals. The enormous concourse of people, the variety of produce exhibited in the market-places of Montezuma’s capital filled the conquerors with wonder and admiration. From Cortés, Bernal Diaz, Sahagun and others we learn that the market was a special charge of the supreme chief of Mexico; that appointed officers presided in state over it whilst others moved among the throng superintending the traffic. Standard measures were kept and rigorous punishment awaited those who sold by false measure or bartered stolen property.” After making the preceding statements I advanced the opinion “that the periodical market-day was the most important regulator of the Mexican social organization and that the monolith generally known as the Calendar-stone was the Market-stone of the City of Mexico. It bears the record of fixed market days; and I venture to suggest that from these the formation of the Mexican Calendar system originated. The stone shows the existence of communal property and of an equal division of general contributions into certain portions....”