You're missing the whole "at the time of Aegons Conquest" part.Was skimming older pages. Overlooked this reply from several months ago.
The riverlands were a kingdom for thousands of years. The definition of a kingdom is a territory under a king. The riverlands were ruled by the King of the Trident.
The last native river king was Damon Teague. House Teague was ruined by House Durrandon from the Stormlands. House Durrandon ran the Trident until they were defeated by House Hoare of the Ironborn.
The Riverlands
King of the Trident
The Targaryens did not create the riverlands, bro.
When Aegon got there, it was Seven Kingdoms. North, Mountain & Vale, Isles and Rivers, The Rock, The Reach, Storm and Dorne.
Seven Kingdoms at the time of his conquest with the Riverlands not being one of them. Nine Kingdoms after his conquest with the Riverlands being one of them.The Targaryens did not create the riverlands, bro.
Hmmmm.