Mandarin (traditional Chinese: 官話; simplified Chinese: 官话; pinyin: Guānhuà; lit. 'official speech') was the common spoken language of administration of the Chinese empire during the Ming and Qing dynasties. It arose as a practical measure, to circumvent the mutual unintelligibility of the varieties of Chinese spoken in different parts of China. Knowledge of this language was thus essential for an official career, but it was never formally defined. The language was a koiné based on Mandarin dialects. The southern variant spoken around Nanjing was prevalent in the late Ming era, although later on a form based on the Beijing dialect took the stage by the mid-19th century and developed into Standard Chinese in the 20th century. In some 19th-century works, it was called the court dialect.