"When the days of rejoicing were over at last the Companions thought of returning to their own homes. And Frodo went to the King as he was sitting with the Queen Arwen by the fountain, and she sang a song of Valinor, while the Tree grew and blossomed. They welcomed Frodo and rose to greet him; and Aragorn said:
'I know what you have come to say, Frodo: you wish to return to your own home. Well, dearest friend, the tree grows best in the land of its sires; but for you in all the lands of the West there will ever be a welcome.'
...'In seven days we will go,' said Aragorn. 'For we shall ride with you far on the road, even as far as the country of Rohan.'"
(Lord of the Rings, The Return of the King)