The thesis deals with how portraits from the early modern period were inventoried, collected and researched in Swedish art history during the period around 1880-1950. It also deals with national portrait galleries and portrait collections as exhibition phenomena in Europe from the 1780s onwards. In the Swedish context, the State Portrait Collection at Gripsholm Castle is of particular interest, as is the Swedish portrait archive initiated and built up at the National Museum during the first half of the 20th century. The thesis shows that portrait painting constituted a quantitatively large part of the total amount of visual art in European countries during the early modern period (1500-1789), while the status of the portrait as art has subsequently been strongly questioned by art historians. Therefore, attention is also drawn to the personal history approach in art history research, which during the period 1880-1950 was devoted to comparing and analyzing the total amount of preserved portraits of rulers from the early modern period, in order to try to determine the real appearance of the depicted person. This in turn raises questions about why it was so important to seek knowledge about how, for example, Gustav Vasa or Gustav II Adolf actually looked? This is also the subject of the final chapter of the thesis, where the interest in the appearance of historical persons is put in relation to a scientific-historical context through physiognomy, i.e. the quasi-scientific doctrine of how external appearance reflects an inner personality.