Is this song unique to the English/Scots language world or are there versions of old origin found in other countries, other languages? If the song is strongly connected with the Craigston story it may be, but there are also suggestions in this discussion that the song travelled across Europe. Also the https://earlymusicmuse.com/the-trees-they-do-grow-high/ article (the link was posted early on in this discussion) mentions some marriages in the French aristocracy:

"On 6th December 1697, Princess Marie Adélaïde of Savoy became the wife of Louis, Dauphin of France and Duke of Burgundy, in the Palace of Versailles. He was 15. It was her 12th birthday.

"On 19th April 1770, Marie Antoinette was legally married by proxy in Vienna to the Dauphin of France. Her new husband, the Dauphin, Louis Auguste, was not only absent – her brother, Archduke Ferdinand, stood in for him – she had never even met him. She did so a month later, on 14th May, with the ceremonial wedding in the Palace of Versailles 2 days later. He was 15. She was 14."

It seems to me highly likely that there are songs in other European languages which are very similar to "The College Boy", "Lang a-growing" etc. Can you suggest any, give any titles and/or lyrics?