When Odysseus failed to return from the Trojan War (he was delayed for ten years on his way home), Penelope was beset by suitors who wanted her to remarry. In order to delay them, she insisted that she could not remarry until she had finished weaving a shroud for Odysseus’ father, Laertes. She worked each day at her loom, and then unravelled the cloth each night. After three years of successful delay, one of her servants revealed her deception, and the impatient suitors angrily demanded that she choose one of them for her husband immediately. At the prompting of Athene, Penelope said that she would marry the man who could string Odysseus’ bow and shoot an arrow through twelve axes. By this time, Odysseus himself had secretly returned, disguised as a beggar; he passed the test of the bow, and then proceeded to slaughter the suitors who had tormented his wife.
http://www.pantheon.org/John William Waterhouse: Penelope and the Suitors – 1912