Board Thread:Lore Discussion/@comment-17114085-20140621192532/@comment-13446185-20140622064930

Tiber Septim destroyed a large amount of royal families throughout Tamriel who were believed to be possible threats to his dynasty with Numidium, and replaced them with rulers more excepting of his reign. I imagine most of these attacks were orchestrated on the families of High Rock and the remnants of the Aldmeri Dominion.

Since Silvenar was a city within the Second Aldmeri Dominion, in my opinion, the most plausible explanation is that Tiber deposed the King of Silvenar and appointed Kintyra in his place.