Rhaegar, despite wounding Robert, was struck down with a massive blow from Robert's warhammer, which scattered the rubies encrusted in Rhaegar's armor under the water.  Rhaegar died with Lyanna Stark's name on his lips.

"Fuck you, Andy Pandy. I AM the loop."

“Fear is a strange soil. It grows obedience like corn, which grow in straight lines to make weeding easier. But sometimes it grows the potatoes of defiance, which flourish underground.”

― Terry Pratchett, Small Gods.