Retroactive nomenclature
Retroactive nomenclature is the telling of the earlier history of a person, place or thing while referring to said person, place or thing by a name that came into use at a later date.
Examples
Names
One easily understandable example of retroactive nomenclature is the tradition in many countries that a woman adopts the surname of the man she marries while remembering her "maiden name" as the way she was referred to her pre-marital days. Radio talk-show host Michael Medved once made the statement: "Hillary Clinton used to be conservative when I knew her in our college days." But in Hillary Rodham's college days she was not yet married to Bill Clinton; therefore there was no "Hillary Clinton" at that time. However, in such a case as this it is easily understood that he meant the woman who later became known as Hillary Clinton.
Similarly, the events of a future monarch's life are often recounted with the regnal name, as in "Queen Victoria was born in 1819". (Princess Alexandrina Victoria of Kent was born in 1819 and became queen in 1837.)
When people today read ancient histories, confusion sometimes results from the fact that in earlier ages historical characters changed their names more often than is common for people to do today, and ancient historians often told earlier stories using later names.
It is possible that King David's name during his boyhood and youth was Elhanan, and his father Jesse, likewise, had the earlier names of Jaare-Oregim and Jair. Although he was not known as "David" until later, one Biblical account (1 Samuel chapter 17) tells the story of his slaying the Philistine giant Goliath, while still calling him David. In 2 Samuel 21:19 he is called Elhanan.
Chinese history
In Chinese history, retroactive nomenclature is widely used by historians when referring to its monarchs and dynasties.
Chinese sovereigns were assigned posthumous titles in the form of posthumous names and temple names after their passing, either by their descendants or by rulers of successive dynasties. For example, Liu Xiu of the Eastern Han dynasty is widely known as the "Emperor Guangwu of Han" with "Guangwu" being his posthumous name. Li Xian of the Tang dynasty is commonly referred to as the "Emperor Zhongzong of Tang" with "Zhongzong" being his temple name. Within the Sinosphere, Vietnam and Korea adopted both posthumous names and temple names, while Japan adopted only posthumous names.
As it was common for Chinese dynasties to adopt the same Chinese characters for their official dynastic name, historians apply prefixes to the names of dynasties in order to distinguish between the numerous similarly-named regimes. For instance, the dynasty founded by Guo Wei is known as the "Later Zhou dynasty", with the prefix "Later" being used to differentiate this particular realm from the Western Zhou dynasty founded by Ji Fa, the Eastern Zhou dynasty established by Ji Yijiu, the Northern Zhou dynasty started by Yuwen Jue, and the Wu Zhou dynasty proclaimed by Wu Zhao, among others.
Other
"Jew" originally meant a person from the nation of Judah (called "Judea" by the Roman Empire), which came into existence after the reign of King Solomon, when the nation of Israel was divided in two. Those from Israel prior to then – the Hebrew slaves in Egypt, as well as the Patriarchs from whom they descended –- were not "Jews" in this technical sense, but Jewish historians still refer to these earlier ancestors as Jews.
The inhabitants of places prior to colonization can take on the name that the land later comes to be known as: Native Americans and Aboriginal Australians are two examples.
"The Day the Music Died" refers to the plane crash that took the lives of rock-and-roll musicians Buddy Holly, Ritchie Valens, and J. P. "The Big Bopper" Richardson in 1959, but was not used popularly until 1971 when singer-songwriter Don McLean coined it in "American Pie".