Answer the question at the end by quoting:

Bernard Lewis, FBA (born 31 May 1916) is a British American historian specializing in oriental studies. He is also known as a public intellectual and political commentator. Lewis is the Cleveland E. Dodge Professor Emeritus of Near Eastern Studies at Princeton University. Lewis' expertise is in the history of Islam and the interaction between Islam and the West.
Lewis' influence extends beyond academia to the general public. He is a pioneer of the social and economic history of the Middle East and is famous for his extensive research of the Ottoman archives. He began his research career with the study of medieval Arab, especially Syrian, history. His first article, dedicated to professional guilds of medieval Islam, had been widely regarded as the most authoritative work on the subject for about thirty years. However, after the establishment of the state of Israel in 1948, scholars of Jewish origin found it more and more difficult to conduct archival and field research in the Arab countries, where they were suspected of espionage. Therefore, Lewis switched to the study of the Ottoman Empire, while continuing to research Arab history through the Ottoman archives which had only recently been opened to Western researchers. A series of articles that Lewis published over the next several years revolutionized the history of the Middle East by giving a broad picture of Islamic society, including its government, economy, and demographics. Lewis argues that the Middle East is currently backward and its decline was a largely self-inflicted condition resulting from both culture and religion, as opposed to the post-colonialist view which posits the problems of the region as economic and political maldevelopment mainly due to the 19th-century European colonization. In his 1982 work Muslim Discovery of Europe, Lewis argues that Muslim societies could not keep pace with the West and that "Crusader successes were due in no small part to Muslim weakness." Further, he suggested that as early as the 11th century Islamic societies were decaying, primarily the byproduct of internal problems like "cultural arrogance," which was a barrier to creative borrowing, rather than external pressures like the Crusades. In the wake of Soviet and Arab attempts to delegitimize Israel as a racist country, Lewis wrote a study of anti-Semitism, Semites and Anti-Semites (1986). In other works he argued Arab rage against Israel was disproportionate to other tragedies or injustices in the Muslim world, such as the Soviet invasion of Afghanistan and control of Muslim-majority land in Central Asia, the bloody and destructive fighting during the Hama uprising in Syria (1982), the Algerian civil war (1992-98), and the Iran-Iraq War (1980-88). In addition to his scholarly works, Lewis wrote several influential books accessible to the general public: The Arabs in History (1950), The Middle East and the West (1964), and The Middle East (1995). In the wake of the September 11, 2001 attacks, the interest in Lewis's work surged, especially his 1990 essay The Roots of Muslim Rage. Three of his books were published after 9/11: What Went Wrong? (written before the attacks), which explored the reasons of the Muslim world's apprehension of (and sometimes outright hostility to) modernization; The Crisis of Islam; and Islam: The Religion and the People.

What other articles did he publish based on his research?

In his 1982 work Muslim Discovery of Europe, Lewis argues that Muslim societies could not keep pace with the West

Answer the question at the end by quoting:

The Oromo people (Oromo: Oromoo; Ge'ez: 'oromo; 'Oromo) are an ethnic group inhabiting Ethiopia and parts of Kenya and Somalia. They are the largest ethnic group in Ethiopia and the wider Horn of Africa. According to the 2007 census, they represent approximately 34.5% of Ethiopia's population, while others estimate they make up about 40% of the population. With the total Ethiopian population thought to be over 102 million, the number of Oromo people exceeds 35 million in Ethiopia alone.
In the late 16th and early 17th centuries, conquests by the Abyssinian Empire in southern and southwestern Ethiopia had left a territorial vacuum, allowing the pastoral Oromo to settle in the vacated territories and incorporate socially dislocated peoples into their gada system. As they moved into earlier Islamic hubs, the Oromos increasingly adopted Islam, and in the process markedly grew their Muslim adherent base to become one of the larger such populations in the Horn region. Pastoralist Oromos also took slaves from their own community's urban areas, as well as from other communities. According to the historian Paul E. Lovejoy, slavery was at this time an important aspect of the social, political and economic structure of parts of Ethiopia. The slaves were classified into two groups: "red" slaves who spoke Afroasiatic languages, and "black" ("Negroid") slaves called Shanqalla who spoke Nilo-Saharan languages. The "red" slaves were primarily courtesans and were more expensive; they were given light duties so as to preserve their looks. The "black" slaves were much less expensive, and toiled in the fields and in Christian Abyssinian households. The "red" slaves, among which were Galla individuals, formed the bulk of captives who were exported from Abyssinian territory to the Arabian peninsula and Persian Gulf regions, to Ottoman Empire markets, to Egypt and elsewhere. Young female Oromo slaves served as concubines and household workers, while males were in demand for private armies and servile labor. Oromos too enslaved other ethnic groups. According to a report by Bermudes, in the 16th century, Oromos during their wars were fierce and cruel, mutilating and enslaving the people in the regions they conquered. Emperor Galawdewos battled with Oromos without much success and sought Portuguese help. In the era of Imam Ahmad, according to Bahrey's records, Oromo Luba 'tribes' made war in Dawaro against Adal Mabraq, devastating the region and occupying it. They also took over Fatagar and Faj, forcing its previous inhabitants into slavery. The pagan Galla and animist Sidama or Agew slaves made up the slave caravans coming out of Ethiopia, as slavers avoided Christian or Muslim slaves. The central Amhara provinces were a part of major Afar slave caravan trade routes from the southern and southwestern Galla, Sidama and Gurage regions to the northern and eastern Ethiopia. Thousands of slaves were exported every year by Jabarti, Jalaba, Afar, Somali and Arab merchants as the income from this trade was lucrative. According to Ira M. Lapidus, a professor of Middle Eastern and Islamic History, the Ethiopian slave trade benefited the Muslims, and increased the Islamization of the Oromo people.

what were some of the regions they conquered?
In the era of Imam Ahmad, according to Bahrey's records, Oromo Luba 'tribes' made war in Dawaro against Adal Mabraq, devastating the region and occupying it.