"Very good lady Mariessa." he sounded content, as if he had expected her to know. "Also, lady Alicent proves to be well read." Simon rewarded the bookish girl with an another smile. He turned to Jynessa. "Lady Jynessa might want to take notes. The history of Reach is important if you want to understand the current situation of the realm. And why wouldn't you. Your future lord husband, the Seven willing, will be relying for your council." Of course chances were her future husband only sought a bed warmer and someone bear him an heir.
Clearing his throat, the young Maester continued, addressing everyone again. "It was indeed house Gardener that commanded the Reach during the Conquest. King, well, back then Reach was a kingdom, Mern the ninth joined forces with the Lannisters to push back the invading Targaryens. While the two armies did manage to break the Targaryen forces, nothing could stand before the dragons and thousands of men burned alive. Including King Mern. Later, Mern's High Steward, Harlen Tyrell, surrendered Highgarden to Aegon I Targaryen. For this Aegon the first granted the Reach to Tyrells that have been the custodians of the lands since." he paused, letting the girls scribble down notes if they so chose to.
"It seems that Lannister king of the time survived and indeed surrendered himself to the Targaryens. Is this correct lady Alicent?" She ought to have known, at least. "However, measter Vaben seems to think that Gardener line did not die with king Mern. See, we have the house Oldflower. Landed knights, no nobler than Tremaine." turning to regard the Tremainer girls, Simon tapped his chin and added. "My ladies, you remember house Oldflower and their arms?"
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OOC:
I'd say TN 12 to recall the arms, TN 18 to recognize that the Oldflowers could be what remains of Gardenersred bend sinister = the sigil of bastard. Alicent would roll at 15 and 21. But you'll get freebie with the story of Loren the first of Lannisters.