In a medieval chronicle "Ajayib-ad-Dunya", written in the 13th century by an unknown author, Arran is said to have been 30 parasangs (200 km) in width, and 40 farsakhs (270 km) in length. All the right bank of the Kura river until it joined with the Aras was attributed to Arran (the left bank of the Kura was known as Shirvan). The boundaries of Arran have shifted throughout history, sometimes encompassing the entire territory of the present-day Republic of Azerbaijan, and at other times only parts of the South Caucasus.