The last time Pluto was in Aries was between 1843 and 1866. During this time period, several historical events occurred that were shaped by the Plutonian themes of power and transformation.

-The California Gold Rush of 1848-1855 brought a flood of people to the region, and it had a profound impact on the economy and society of the American West. The sudden influx of wealth and people led to the rise of new power structures and the emergence of new leaders.

-The Taiping Rebellion in China was a massive civil war that lasted from 1850 to 1864. It was marked by a struggle for power between different factions and it ultimately led to the deaths of millions of people. The rebellion also had a transformative effect on Chinese society and politics.

-The American Civil War, which lasted from 1861 to 1865, was another significant event that occurred during this time period. It was a struggle for power between the northern and southern states, and it led to the abolition of slavery and the emergence of a new power structure in the United States.

-The Industrial Revolution was already in full swing during this time, and it brought about significant changes in the way goods were produced and distributed, which led to a change in the power dynamics of society.

These events all had significant impacts on the power structures and societies of their respective regions, and they were all marked by transformative changes and struggles for power, aligning with the themes of Pluto in Aries.