"The imposter magician Smerdis" is mentioned in the short story by Jorge Luis Borges, Tlön, Uqbar, Orbis Tertius.
"Tlön, Uqbar, Orbis Tertius", a short story by the 20th century Argentine writer Jorge Luis Borges
Nonetheless, there is at least one real place with the name Uqbar, in Algeria, as well as a town called Ukbara in Iraq, each of which seems to have at least some aspects in common with Borges's fictional Uqbar.
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On the left bank of the Tigris between Samarra and Baghdad was the city of ‘Ukbarâ (عكبرا, q. v.), located along a river that flows southward out of Asia Minor, and the birthplace of at least two Jewish "heresiarchs", who led the "Okbarite" heretical movement within Karaism, itself a heresy in the eyes of orthodox Judaism.