Emperor Xianzong of Tang vs Krum the Fearsome

Emperor Xianzong initiated the Yuanhe Restoration, a series of reforms aimed at centralizing power and curbing the autonomy of military governors (jiedushi). He reasserted imperial authority over several rebellious provinces, strengthening the Tang state.

Emperor Xianzong launched a military campaign against the Chengde Circuit, a rebellious province in Hebei. After initial setbacks, the Tang forces secured a victory, forcing the Chengde governor to submit to imperial authority.

Emperor Xianzong's forces conquered the Zhaoyi Circuit, a rebellious province in modern Shanxi. This victory further reduced the power of the military governors and strengthened imperial control.

Emperor Xianzong launched a campaign against the Pinglu Circuit in Shandong. The Tang forces defeated the rebel governor, bringing the province back under imperial control and completing the Yuanhe Restoration's military successes.

Emperor Xianzong died suddenly, possibly poisoned by eunuchs. His death ended the Yuanhe Restoration, and subsequent emperors were unable to maintain the centralization he achieved, leading to the Tang dynasty's further decline.

Krum introduced a set of laws aimed at centralizing power and unifying the Bulgarian state. These laws included measures against theft, drunkenness, and false oaths, and established a uniform legal system.

Krum led the Bulgarian army to a decisive victory over the Byzantine Empire at the Battle of Pliska. Byzantine Emperor Nikephoros I was killed in the battle, and his skull was later used as a drinking cup by Krum.

Krum besieged Constantinople after a series of victories over the Byzantines. He failed to capture the city due to its strong defenses and the death of Krum shortly after, but the siege demonstrated Bulgarian military power.