Where does “Ասպահան” come from?

Ասպահան (Armenian) comes from Old Armenian Ասպահան, from Old Median Spādānah, from Old Persian 𐎿𐎱𐎠𐎭, from Proto-Iranian *cwáHdah, from Proto-Indo-Iranian *ćwáHdʰaH, from Proto-Indo-European ḱwéh₁-dʰ-o-h₁.