Scenes from the 2016 World Nomad Games hosted in Cholpon-Ata, Kyrgyzstan. The World Nomad Games brings athletes from various countries, primarily from the Central Asian region and Russia, to participate in sports native to the Eurasian Steppe. The Eurasian Steppe was home to various nomadic peoples particularly the Iranic-speaking Scythians and Sarmatians, who were a source of fear for the ancient Greeks due to their warriorlike nature and great horse-riding skills; including their mastery of horseback archery. Both groups are believed to have originated in the Eurasian Steppes, but their settlements ranged from China to Poland, and because of this they greatly impacted the genetic pool and cultures of a number of different groups in Eastern Europe and Central Asia such as the people of the Caucasus, Slavs, Turkic people, and other modern Iranic people. The Sarmatians in particular were famed by Greek historians for their female warriors and rulers that inspired the stories of the Amazons.
I'm trying to worldbuild a Holy Roman Empire-style Kingdom made up of six regions, who remained distinct till one Prince took control of others. I plan for another region to be particularly good for cavalry, so what areas would produce good cavalry forces?