Complex sentence: In the 1950s, Iraq was awash with new oil money; the deal negotiated in 1950 with the Western-controlled Iraq Petroleum Company, which held a monopoly on oil exploration and development, increased the government's share of revenues substantially.
Split into simpler sentences: In the 1950s, Iraq was awash with new oil money. The deal negotiated in the first years of the decade with the Western-controlled Iraq Petroleum Company, which held a monopoly on oil exploration and development, increased the government's share of revenues substantially.