Khuzestan has been a troublesome province of Iran since the ascent of the Pahlavi rule in the 1920s. In the two decades before 1924, although nominally part of Persian territory, the western part of Khuzestan functioned as an autonomous emirate known as "Arabistan". The eastern part of Khuzestan was governed by Bakhtiari khans because the eastern part of Khuzestan was mainly inhabited by Bakhtiari people. With rising power of Reza Khan and his increasingly negative attitudes on tribal autonomies in Iran, tensions with shaikh Khazal of Mohammerah had grown from 1922 to 1924. Attempts to withdraw more taxes and reduce Khazal's authority heated it up even more. In response Khaz'al al-Ka'bi initiated a rebellion. The short rebellion by Sheikh Khazal, at its peak in November 1924, was quickly crushed by the newly installed Pahlavi dynasty with minimal casualties. The emirate was dissolved by Reza Shah government in 1925, along with other autonomous regions of Persia, in a bid to centralize the state. At least 115 people died in the insurrection. A low level conflict between the central Iranian government and the Arab separatists of the western part of the province continued since.
Question: What event happened first, the ascent of the PHlavi rule, or the western part of Khuzestan became Arabistan?
Answer: western part of Khuzestan became Arabistan