The York Retreat is famous in the history of nineteenth-century psychiatry because of its association with moral treatment. Although there exists a substantial historical literature on the evolution of moral treatment at the Retreat, several interpretive problems continue to obscure its unique therapeutic legacy. The nature of moral treatment as practised at the Retreat will be clarified and discussed in a historical perspective. It will be argued that moral treatment at the Retreat was primarily a matter of affective conditioning guided by 'benevolent theory'.