I don’t know if it was Houthis or Yemanis in general, but I read an interesting tidbit in a book about the major eruption of Krakatoa in the 1880s. I think the author was Simon Winchester. One result of this disaster was that Muslims in that area decided their Dutch colonialists had lost “the mandate of heaven” and hence moved to overthrow them. Specifically, Muslims were visiting Yemen after their trips to Saudi Arabia for the annual Hajj celebrating their religion. It seems that Yeman was a center of Islamic fundamentalism and planning for the future, so what is happening there today is definitely not a new development in Islamic aggression for people living there.
Sudan was a troubled region in the late 19th century:
Mohammed Ahmed was a messianic Islamic leader in central and northern Sudan in the final decades of the 19th century. Claiming that Allah had selected him as the true Mahdi, he found fertile political ground in the inhabitants’ resentment engendered by the corruption of and oppression by Egyptian rulers who had long dominated the region. Economic and political problems in Egypt further strengthened the Mahdi’s hand, enabling the Mahdi’s forces and followers to occupy most of the Sudan. In 1883 the Mahdists overwhelmed the Egyptian army of British commander William Hicks, and Great Britain ordered the withdrawal of all Egyptian troops and officials from the Sudan. In 1885, General Gordon famously lost his life in a doomed defence of the capitol, Khartoum, where he had been sent to lead evacuation of Egyptian forces. Though the Mahdi died in 1885, his theocracy continued until 1898, when the British general Kitchener reoccupied the Sudan.