The period of the third shōgun, Iyemitsu (1624-1651), perhaps marks the height of the vigor and efficiency of the Tokugawa feudalism. He was assisted by able councilors, and his strong administration was emulated by many great local barons in their respective fiefs, so that a profound peace reigned over the country broken only by the Christian insurrection at Shimabara. From the latter half of the seventeenth century, however, signs of the decline of the Edo power began to manifest themselves. At the accession of the fourth shōgun, Iyetsuna (1651-1680), Yuino Shōsetsu and Marubashi Chūya, two military captains not attached to any feudal baron, collected a great number of _rōnin_ ("wave men," _samurai_ attached to no lord) in Suruga and in Edo, their project being to raise the standard of revolt simultaneously in the west and in the east. Their attempt was unsuccessful, but its failure did not deter two other _rōnin_ from plotting a similar insurrection in Edo the following year. They, too, were discovered and punished before their plans matured. Thereafter, for a time, owing doubtless to the fact that the feudal barons were too frequently deprived of their estates, their vassals found themselves homeless and resourceless, and the peace of the country was broken here and there by bands of _rōnin_. These troubles, however, were speedily dealt with. Nor was the Edo castle itself free from trouble, for toward the close of Iyetsuna's shōgunate, the _tairō_, Sakai Tadakiyo, acquired so much influence that the authority of the shōgun himself was somewhat impaired. The next shōgun, Tsunayoshi (1680-1709), however, returned to the vigorous policy of the first three of his predecessors. He dismissed Tadakiyo, and appointed Hotta Masatoshi, a statesman of great acumen, in his stead as _tairō_. The shōgun and his ministers alike devoted themselves unwearyingly to promoting the welfare of the country. This era is worthy of close attention. We find, among other things, that Tsunayoshi greatly encouraged the study of literature. Tokugawa Iyeyasu, though essentially a soldier and statesman, fully appreciated the importance of literature, which he conceived as an indispensable factor in encouraging the pursuit of virtue and promoting the peace of society. Even while his hands were busy with campaigns and battles, he invited great savants and listened to their lectures on the Chinese classics. He also caused his officers to collect and reprint valuable books that would otherwise have been lost to the nation. His three successors followed his example in this respect, but it was the fifth shōgun, Tsunayoshi, who above all contributed to the spread of literary pursuits. Devoted from his youth to the study of the Chinese classics, he made a habit, after his succession, of delivering lectures to the feudal barons and vassals, and Shintō and Buddhist priests, and it may well be supposed that this action gave a great impetus to literary pursuits.