This chapter discusses Iranian nationalism during the years of Reza Khan’s rise as a nationalism rooted in territorial concepts. It describes how the emerging military rule of Reza Khan coalesced with the foreign policy efforts of the Iranian statesmen until parliamentary politics were overshadowed by the military’s arbitrary rule. Against this backdrop, the greater part of the chapter is devoted to depicting Iran's policy toward the Persian Gulf and toward the Arab shaykhdoms in the Gulf during the period of Reza Khan's rise, and the rhetoric and conduct of Iranian officials in the port towns and islands where the paths of Arabs and Iranians from different walks of life intersected. The assertion of central authority over Arabistan (renamed Khuzestan) is viewed as a decisive step in Iran’s more ambitious goal of reducing British influence in the Persian Gulf waterway, islands, and littoral.