States and territories established in the 820s

Basque medieval kingdom that occupied lands on either side of the western Pyrenees, alongside the Atlantic Ocean (1162–1512)

Iranian dynasty ruling Khorasan (821–873)

Muslim state that existed on the Mediterranean island of Crete from the late 820s to the reconquest of the island by the Byzantine Empire in 961

former province of Japan

Chaldia (, Khaldia) was a historical region located in the mountainous interior of the eastern Black Sea, northeast Anatolia (modern Turkey) in Western Asia. Its name was derived from a people called the Chaldoi (or Chalybes) that inhabited the region in antiquity. Chaldia was used throughout the Byzantine period and was established as a formal theme, known as the Theme of Chaldia (Greek: θέμα Χαλδίας), by 840. During the Late Middle Ages, it formed the core of the Empire of Trebizond until its fall to the Ottoman Empire in 1461.

former independent kingdom in present-day Uttarakhand, India

Byzantine administrative unit (theme)