Q: In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
Passage: Along with the Sceptre of Annuminas, the Star of Elendil was the chief symbol of the royal line of Arnor. The original jewel was fashioned of "elvish crystal" by the Noldor and affixed to a fillet of mithril, to be worn in the custom of Numenor on the brow in place of a crown. This was worn by Silmarien of Numenor and passed to her descendants, the Lords of Andunie, and eventually to Elendil. Elendil and then his son Isildur wore it as a token of royalty in the North Kingdom, but it was lost in the Anduin when Isildur was slain by orcs at the Gladden Fields. A replacement was fashioned by elves in Rivendell for Isildur's son Valandil, and this second jewel was borne by the subsequent thirty-nine kings and chieftains of Arnor, up to and including Aragorn.
Link Information: none Question: In what year was Isildur slain at Gladden Fields?
A:
Answer: none