The letters Bishop Edward Synge (1691-1762) wrote to his daughter Alicia (1733-1807) in 1747-1752 are discussed to show how correspondence from a father to a daughter could be used to teach a teenage girl how to spell and write letters. Moreover, these letters are an excellent source to show how emotional behaviour was taught. Instructions on letter-writing were inextricably connected to advice on general manners. At the base of both lay Synge's ideas on emotional composure. He taught his daughter emotional self-restraint in writing and behaviour. Synge's ideas on emotions can be traced to the eighteenth-century ideal of politeness, of which restraint in the display of emotions formed a part. In addition, Synge's views on emotion and education are compared with those of his friend, the Irish-Scottish philosopher Francis Hutcheson (1694-1746). Furthermore, the letters Synge wrote to his daughter are similar to the letters Lord Chesterfield (1694-1773) wrote to his son from 1737. In both correspondences there is a tension between the ideal of politeness and the way polite behaviour can compromise sincerity. Chesterfield instructed his son to dissimulate, to hide his true emotions. Synge tried to find a balance between polite manners and sincerity, but wrote that, if necessary, custom might prevail over sincerity. The Synge correspondence belonged to an older emotional culture, in which polite self-restraint was of utmost importance. A few decades later, the cult of sensibility would become popular, in which the expression of emotions would be encouraged. (Contains 75 footnotes.)