excerpts-from-tolkien:

“…[A]nd even as he felt the stream slacken and had almost won across he found himself struggling among great rushes and clinging weeds. There suddenly he knew that the Ring had gone. By chance, or chance well used, it had left his hand and gone where he could never hope to find it again. At first so overwhelming was his sense of loss that he struggled no more, and would have sunk and drowned. But swift as it had come the mood passed. The pain had left him. A great burden had been taken away. His feet found the river bed, and heaving himself up out of the mud he floundered through the reeds to a marshy islet close to the western shore. There he rose up out of the water: only a mortal man, a small creature lost and abandoned in the wilds of Middle-earth. But to the night-eyed Orcs that lurked there on the watch he loomed up, a monstrous shadow of fear, with a piercing eye like a star. They loosed their poisoned arrows at it, and fled. Needlessly, for Isildur unarmed was pierced through heart and throat, and without a cry he fell back into the water. No trace of his body was ever found by Elves or Men. So passed the first victim of the malice of the masterless Ring: Isildur, second King of all the Dúnedain, lord of Arnor and Gondor, and in that age of the World the last.”

—J.R.R. Tolkien, Unfinished Tales, “The Disaster of the Gladden Fields” (Isildur’s death)