We use historical publications and micro data from the tax returns to construct internationally comparable estimates of the development in income inequality in Denmark over the last 140 years. The study shows that income inequality and top income shares have declined during several distinct phases in between periods of stability. Furthermore the quality of the Danish data allows us to analyse not only the development in top income shares but also broader inequality measures such as the Gini coefficient. These analyses show that top income shares are a good proxy for the underlying development in inequality.