to flee to Brazil (on English ships), from where they ruled until 1821. By the time King João VI returned to Lisbon, he faced a nobility divided in their support for him personally, plus a middle class that wanted a constitutional monarchy. During Joao VI's reign (1821–1826) and that of his successors—Peter IV (1826–1831), Maria (1833–1853), Peter V (1853–1861), Louis I (1861–1889), and Carlos (1889–1908)—there was a civil war that lasted from 1826 to 1834, a long period characterised by what one author called "ministerial instability and chronic insurrection" from 1834 to 1853, and finally the end of the monarchy when both Carlos and his heir were assassinated on February 1, 1908. Under those circumstances, colonial officials appointed by governments in Lisbon were more concerned with politics at home than with administering their African territories. As it did everywhere else, the Industrial Revolution stimulated change in Portuguese Africa. It created a demand for tropical raw materials like vegetable oils, cotton, cocoa and rubber, and it also created a need for markets to purchase the expanded quantity of goods issuing from factories. In Portugal's case, most of the factories were located in England, which had had a special relationship with Portugal ever since Philippa, the daughter of England's John of Gaunt, married John of Avis, the founder of the Portuguese second dynasty. Prodded by Napoleon's invasion and English support for the royal family's escape to Brazil, King João and his successors eliminated tariffs, ended trade monopolies and generally opened the way for British merchants to become dominant in the Portuguese empire. At times, that caused friction, such as when both British and Portuguese explorers claimed the Shire Highlands (located in modern Malawi), but for the most part Great Britain supported the Portuguese position in exchange for incorporating Portugal's holdings into the British economic sphere. With neither a large European population nor African wage earners, the Portuguese colonies offered poor markets for manufactured goods from the private sector. Consequently, industrialisation arrived in the form of government programs designed to improve internal communications and increase the number of European settlers. During the late 1830s, the government headed by Marquis Sá da Bandeira tried to encourage Portuguese farmers to migrate to Angola, with little success. Between 1845 and 1900, the European population of Angola rose from 1,832 to only about 9,000. European migration to Mozambique showed slightly better results—about 11,000 in 1911—but many were