Denmark experienced major socioeconomic changes, including overall population growth, during the Viking, medieval and post-medieval periods from ca. AD 800 to 1800. Archaeological skeletons provide a unique perspective on the population structure of Ribe, a Danish town in Jutland, during the millennium that immediately precedes the industrialization of northern Europe. This skeletal study adds temporal depth to our understanding of an overall trend toward longer life as seen from historical records and in modern studies. Adult male and female mean age at death and mortality profiles during three time periods are based on 943 adult skeletons from three urban cemeteries that collectively represent a cross-section of this urban community. For both males and females, the mean age at death decreased slightly from the Viking (males 38.5 years, females 38.6 years) to the medieval (males 37.4 years, females 36.9 years) periods. This decline was followed by an increase in mean age at death for both sexes from the medieval to post-medieval (males 40.4 years, females 43.2 years) periods, a notable gain of 3.0 and 6.3 years for men and women, respectively.