Related to the Bunga Mas^1:

According to a Kedah source, the first time a bunga mas was sent, it was sent as a toy for a new-born Thai prince who was the grandson of Sultan of Kedah himself since his kin, a princess was married to the Thai king^1.

This then set the precedence of Malay Sultans being "required" one way or another to send Bunga Mas to Siam. The culmination of the meme is the Siamese invasion of Kedah in 1821^2 partly due to the Sultan ceasing sending bunga mas, making Kedah Sultanate, the progenitor of the practice, existn't for a time.