The exact date of the contruction of Ankara Castle is unknown but it is known that it was under the control of Romans and Byzantines. Seljuq Turks started to control the castle in 1073. The current construction was renovated in 1832 during the Ottoman era.
The castle is surrounding the Old Ankara. If you visit the modern capital of Turkey and also want to see the historic Ankara, you should definetely visit Ankara Castle and the surrounding.