During the caliphate of Abu Bakr (), the Muslims led by Khalid ibn al-Walid may have launched their first campaigns against the Sasanian Persians in lower Mesopotamia (Iraq), but these their gains were short-lived or limited. Abu Bakr's successor Umar () dispatched Utba to this front from the capital at Medina, which marked the commencement of the definitive conquest of Iraq. His force was relatively small, ranging from 300 to 2,000 men, according to the medieval Arabic sources. Its ranks were dominated by members of the Banu Thaqif,with whom Utba had marital links, and partly consisted of nomadic Arab tribesmen who joined Utba's army while it was on the move. Utba launched an assault against the town of Ubulla and its 500-strong garrison of Persian cavalry. He set up camp at a nearby village called Khurayba, then bested Ubulla's defenders and occupied and plundered the town. He installed one of his lieutenants, his brother-in-law Nafi ibn al-Harith ibn Kalada, to guard the town, which he used as a base of operations against other Sasanian positions in the area. He and/or his lieutenant commanders al-Mughira ibn Shu'ba and Mujashi ibn Mas'ud al-Sulami thereafter captured the towns of al-Furat and Maysan and the districts of Abazqubadh and Dast Maysan, all located along the lower Tigris river banks. Graeme Porter  Graeme David Porter (born 18 March 1955) is a former Australian international cricketer. He played in two 1979 Cricket World Cup matches in England as a medium pace bowler taking three wickets at an average of 11.00. He also took 52 wickets in 32 first-class matches for Western Australia. After retiring from professional cricket, he taught mathematics at Trinity College, Perth and at Kent Street Senior High School, where he also coached their cricket scholarship team. His son, Drew Porter, also played for Western Australia. Olswang  Olswang was an international law firm headquartered in London, United Kingdom and with additional offices in Reading, Brussels, Madrid, Paris, Singapore  and, since 2011, Munich. It worked closely with a network of firms across eighty countries. "The Lawyer" ranked the firm 22nd largest in the UK by worldwide turnover in 2010. That year, the firm had over 600 staff, including 97 partners. David Stewart was the firm's chief executive.