Here is a reference for you to answer your question:Very nice library, but one thing: I thought that building from Samarra was a Ziggurat (or however it's spelled in English)...... not a Mosque! Was it turned into a Mosque later?
http://gallery.sjsu.edu/IslamicTutorial/Samarra/samara.html said:Built around 848-849
The Great Mosque was the Abbasid capital in central Iraq. It is one of the largest mosque taking up 240 x 160 m, and was built with baked bricks. The most famous feature is the spiral minaret, also called the Malwiyya. The minaret reach up 52 meters and may have been influenced by the earlier Mesopotamian ziggurats.