Complex sentence: This period was one of relative peace under the authority of the Tokugawa shogunate, a forced peace that was maintained through a variety of measures that weakened the "daimyōs" and ensured their loyalty to the shogunate.
Split into simpler sentences: This period was one of relative peace under the authority of the Tokugawa shogunate. This was a forced peace--maintained through a variety of measures that weakened the "daimyōs" and ensured their loyalty to the shogunate.