Complex sentence: Three years later, he established the Tokugawa Shogunate, a powerful entity that would maintain peace, stability, and prosperity in Japan for the following 250 years, this is known as the Edo period (1603-1868).
Split into simpler sentences: Three years later, he established the Tokugawa Shogunate, a powerful entity that would maintain peace, stability, and prosperity in Japan for the following 250 years. This is known as the Edo period (1603-1868).