Farsakh

The parasang is a historical Iranian unit of itinerant distance, the length of which varied according to terrain and speed of travel. The European equivalent is the league.

The parasang may have originally been some fraction of the distance an infantryman could march in some predefined period of time. Mid-5th-century BCE Herodotus (v.53) speaks of [an army] traveling the equivalent of five parasangs per day.

In antiquity, the term was used throughout much of the Middle East, and the Old Iranian language from which it derives can no longer be determined (only two—of what must have been dozens—of Old Iranian languages are attested). There is no consensus with respect to its etymology or literal meaning. In addition to its appearance in various forms in later Iranian languages (e.g. Middle Persian frasang or Sogdian fasukh), the term also appears in Greek as parasangēs (παρασάγγης), in Latin as parasanga, in Hebrew as parasa (פרסה), in Armenian as hrasakh (հրասախ), in Georgian as parsakhi, in Syriac as parsḥā (ܦܪܣܚܐ), in Turkish as fersah, and in Arabic as farsakh (فرسخ). The present-day New Persian word is also farsakh (فرسخ), and should not be confused with the present-day farsang (فرسنگ), which is a metric unit.

The earliest surviving mention of the parasang comes from the mid-5th-century BCE Herodotus (Histories ii.6, v.53, vi.42), who defines the measure to be equivalent to 30 stadia, or half a schoenus. A length of 30 stadia is also given by several later Greek and Roman writers (10th-century Suidas and Hesychius, 5th/4th-century BCE Xenophon Anab. ii.2.6). The 6th-century Agathias (ii.21) however—while referring to Herodotus and Xenophon—notes that in his time the Pérsai considered the parasang to have only 21 stadia. Strabo (xi.xi.5) also notes that some writers considered it to be 60, others 40, and yet others 30. In his 1st-century Parthian stations, Isidore of Charax "evidently [used for schoenus] the same measure as the Arabic parasang (while in Persia proper 4 sch[onii] equal 3 par[asang])."

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