Mandela was sent to Robben Island prison off the coast of Cape Town in 1964 where conditions were bad and he performed hard labor in a quarry. He was allowed 6 month visits and letters and continued his studies. Over 3,000 other African political prisoners were also held in small cells. Mandela became a leader to the prisoners and helped set up an informal school. Conditions worsened over time even as more prisoners arrived and family visits became less frequent.