A sultanate on the southeast coast of the arabian peninsula. Its capital is masqat. Before the 16th century it was ruled by independent emirs but was captured and controlled by the portuguese 1508-1648. In 1741 it was recovered by a descendent of yemen's imam. After its decline in the 19th century, it became virtually a political and economic dependency within the british government of india, retaining close ties with great britain by treaty from 1939 to 1970 when it achieved autonomy. The name was recorded by pliny in the 1st century a.d. As omana, said to be derived from the founder of the state, oman ben ibrahim al-khalil.