The reason why the queen resorted to using military force to strengthen her authority in the East is unclear;[6] but the refusal of Roman officials to recognize Palmyrene authority has been suggested as a reason, so Zenobia's expeditions were intended to maintain Palmyrene dominance.[7] Another factor may have been the weakness of Roman central authority and its corresponding inability to protect the provinces, which harmed Palmyrene trade and probably convinced Zenobia that the only way to maintain stability and prosperity in the Roman East was direct Palmyrene control over the region.[7] Also, Bostra and Egypt received trade which would have otherwise passed through Palmyra,[8] while the Tanukhids near Bostra and the merchants of Alexandria probably attempted to rid themselves of Palmyrene domination, all of which triggered military action from the queen.[8]