In October 1835 at the age of 17, Marx travelled to the University of Bonn wishing to study philosophy and literature, but his father insisted on law as a more practical field. Due to a condition referred to as a "weak chest", Marx was excused from military duty when he turned 18. While at the University at Bonn, Marx joined the Poets' Club, a group containing political radicals that were monitored by the police. Marx also joined the Trier Tavern Club drinking society () where many ideas were discussed and at one point he served as the club's co-president. Additionally, Marx was involved in certain disputes, some of which became serious: in August 1836 he took part in a duel with a member of the university's Borussian Korps. Although his grades in the first term were good, they soon deteriorated, leading his father to force a transfer to the more serious and academic University of Berlin.