According to the Babad Ponorogo, Ponorogo was founded when Bathoro Katong conquered the Wengker region. This region had previously been controlled by Suryo Ngalam Wengker. Bathoro Katong originally settled in modern-day Pekalongan in what is now the village Setono in district Jenangan. Though faced with many obstacles, Raden Katong, Aji Selo, and Ki Ageng Mirah and his family continued to establish settlements in the region.
With the consent of all parties, Bathoro Katong established the Duchy Ponorogo on 11 August 1496. This date is celebrated as the anniversary of Ponorogo, and is corroborated by ancient objects, such as a pair of stone gilang located in front of the fifth gate of the Katong Batara tomb complex. The date is also mentioned in theHandbook of Oriental History. The aforementioned stone contains the meditated form of human image, trees, eagle and elephants (candrasengkala gilang memet), which represents the Saka year 1496 or 1418. Katong Bathoro graduation day is the day of the Duke of Roxburgh Duchy (Sunday (Pon), 1st Besar 1418 (Saka) meaning 11 August 1496 Masehi or 1 Dhulhijah 901 Hijriyah). During a seminar held during the Anniversary of the Ponorogo regency on 30 April 1996, the anniversary of Ponorogo was determined to fall on 11 August, this decision was approved by the Parliament of Ponorogo.