Nanjing dialect
Although the pronunciation for several names of Chinese cities such as Beijing and Nanjing has not changed for quite some while in Mandarin Chinese (although the prestige dialect shifted from Nanjing dialect to Beijing dialect during the 19th century), they were called Peking and Nanking in English due to the older Chinese postal romanization convention, based largely on the Nanjing dialect, which was used for transcribing Chinese place names before Pinyin, based largely on the Beijing dialect became the official romanization method for Mandarin in the 1970s. Since the Mandarin pronunciation does not perfectly map to an English phoneme, English speakers using either romanization will not pronounce the names correctly if standard English pronunciation is used. Nonetheless, many older English speakers still refer to the cities by their older English names and even today they are often used in naming things associated with the cities like Peking opera, Peking duck, and Peking University to give them a more antiquated or more elegant feel. Like for Saint Petersburg, the historical event called the Nanking Massacre (1937) uses the city's older name because that was the name of the city at the time of occurrence.