Society in the Japanese "Tokugawa period" (Edo society), unlike the shogunates before it, was based on the strict class hierarchy originally established by Toyotomi Hideyoshi. The daimyo, or lords, were at the top, followed by the warrior-caste of samurai, with the farmers, artisans, and traders ranking below. In some parts of the country, particularly smaller regions, daimyo and samurai were more or less identical, since daimyo might be trained as samurai, and samurai might act as local lords. Otherwise, the largely inflexible nature of this social stratification system unleashed disruptive forces over time. Taxes on the peasantry were set at fixed amounts which did not account for inflation or other changes in monetary value. As a result, the tax revenues collected by the samurai landowners were worth less and less over time. This often led to numerous confrontations between noble but impoverished samurai and well-to-do peasants, ranging from simple local disturbances to much bigger rebellions. None, however, proved compelling enough to seriously challenge the established order until the arrival of foreign powers.