Achaemenid Arabia

Arabia or Achaemenid Arabia was a satrapy (province) of the Achaemenid Empire by the name of Arabâya. Achaemenid Arabia corresponded to the lands between Nile Delta (Egypt) and Mesopotamia, later known to Romans as Arabia Petraea. According to Herodotus, Cambyses did not subdue the Arabs when he attacked Egypt in 525 BCE. His successor Darius the Great does not mention the Arabs in the Behistun inscription from the first years of his reign, but does mention them in later texts. This suggests that Darius might have conquered this part of Arabia^[1]or that it was originally part of another province, perhaps Achaemenid Babylonia, but later became its own province. This could mean that the Arabs were in fact conquered by Cyrus the Great

Arabs were not considered as subjects to the Achaemenids, as other peoples were, and were exempt from taxation. Instead, they simply provided 1,000 talents of frankincense a year. They also helped the Achaemenids invade Egypt by providing water skins to the troops crossing the desert.^[2]

References

Provinces of the Achaemenid Empire (Behistun / Persepolis / Naqsh-e Rustam / Susa / Daiva inscriptions)
Arabia Arachosia Aria Amyrgoi Armenia Assyria Babylonia Bactria Cappadocia Caucasian Albania Caria Cilicia Colchis Chorasmia Carmania Dahae Drangiana 1st Egypt / 2nd Egypt Eber-Nari Elam Gandhara Gedrosia Hyrcania Ionia Hindush Libya Maka Media Lesser Media Massagetae Parthia Persia Phoenicia Phrygia Hellespontine Phrygia Greater Phrygia Saka Samaritan Province Lydia Sattagydia Thrace Sogdia Yehud
See also Districts of the Achaemenid Empire (according to Herodotus)