Thank you for starting this thread, Nellie. As I was typing my last post under the Diamond Diadem thread, I wondered about the history of coronations.

Wikipedia has this to add about the very early history of coronations:

"Coronations, in one form or another, have existed since ancient times. Egyptian records show coronation scenes, such as that of Seti I in 1290 BC,[1] while the Judeo-Christian scriptures testify to particular rites associated with the conferring of kingship, the most detailed accounts of which are found in II Kings 11:12 and II Chronicles 23:11. These Biblical accounts influenced later European ceremonies, together with those of Ethiopia and Tonga, following the conversion of those lands to Christianity.[2] In non-Christian states, coronation rites evolved from a variety of sources, often related to the religious beliefs of that particular nation. . . .

"In some European Celtic or Germanic countries prior to the adoption of Christianity, the ruler upon his election was raised on a shield and, while standing upon it, was borne on the shoulders of several chief men of the nation (or tribe) in a procession around his assembled subjects. This was usually performed three times. Following this, the king was given a spear, and a diadem wrought of silk or linen (not to be confused with a crown) was bound around his forehead as a token of regal authority. . . ."

Edit: These quotations are from the article "Coronation." There is a lot more detail in the "Coronations in Antiquity" article in Wikipedia.