At around age 12, the boys would enter into an institutionalized relationship with a young adult male Spartan. Plutarch described this form of Spartan pederasty (erotic relationship) as one where older warriors would engage promising youths in a long-lasting relationship with an instructive motive. However Xenophon, an Athenian friend of King Agesilaus II and whose sons were given the honour of training in the Agoge, comments that the laws of Lycurgus strictly prohibited sexual relationships with the boys. According to Plutarch, the older Spartans were their Captains during combat and their master at home. The older boys were often instructed to collect wood, while the weaker and unfit boys gathered things such as salad and herbs. The boys were expected to request the relationship, which was seen as a method to pass on knowledge and maintain loyalty on the battlefield. At the stage of "paidiskoi", around the age of 18, the students became reserve members of the Spartan army. Some youths were allowed to become part of the Crypteia, a type of 'Secret Police', the members of which were instructed to spy on the Helot population. They would also kill Helot slaves who were out at night or spoke about rebelling against the Spartan government, in order to keep the population submissive. The state supported this by formally declaring war on the Helots every autumn. This meant killing a Helot was not regarded as a crime, but a valuable deed for the good of the state.