historical materials, dated according to two different chronological systems. For the compilers of the famous chronicle sometimes mistook one and the same event found in different sources and given in two different chronological systems, for two independent events resembling each other only in certain superficial respects. Otherwise they misunderstood two entirely distinct events having the same cyclical designation in date as a single occurrence, narrated in two different ways, ignoring the fact that there might have been two like events which happened at a chronological distance of sixty years or some multiple of that cycle of time. Confusion of this kind was unavoidable in ages where there was no established method of defining a historical date. It was a great gain, therefore, that astronomy and the art of calendar-making chanced to be introduced in 602 A.D., the tenth year of the reign of the Empress. Another not less important boon which we received from China through the peninsular states was the gradation of official ranks. Anterior to this period we had something like a hierarchical system with the emperor as the political and social supreme, but the system, if it could be called such, was nothing but a chain of vassalship fastened very loosely. It was far from a well-ordered gradation, which is in reality the beginning of equalisation and could only be effected by a very strong hand. The dignity of the emperor could be excellently upheld by having under him gradated subjects, but the gradation itself did not hinder those subjects from thinking that they were equals before the emperor as his subjects. This gradation came into practice in the year 604 A.D. In the same year the famous "Seventeen Articles" was also promulgated. This was a collection of moral maxims imparted to all subjects, especially to administrative officials, as instructions. The principle pervading the articles unmistakably betrays that much of it was borrowed from Chinese moral and political precepts. The only exception is the second article, which encouraged the worship of Buddha. It was natural that such articles should be decreed by Prince Shotoku, who was under the tutorship of a Korean priest and a naturalised peninsular savant.