The Roman Empire (Latin: Imperium Romanum) was the post-Republican period of the ancient Roman civilization, characterized by an autocratic form of government and large territorial holdings around the Mediterranean in Europe, Africa, and Asia. The 500-year-old Roman Republic, which preceded it, had been destabilized through a series of civil wars. Several events marked the transition from Republic to Empire, including Julius Caesar's appointment as perpetual dictator (44 BC); the Battle of Actium (2 September 31 BC); and the granting of the honorific Augustus to Octavian by the Roman Senate (16 January 27 BC).
iOS (previously iPhone OS) is a mobile operating system developed and distributed by Apple Inc. Originally released in 2007 for the iPhone and iPod Touch, it has been extended to support other Apple devices such as the iPad and Apple TV. Unlike Microsoft's Windows Phone (Windows CE) and Google's Android, Apple does not license iOS for installation on non-Apple hardware. As of September 12, 2012, Apple's App Store contained more than 700,000 iOS applications, which have collectively been downloaded more than 30 billion times.