Philip supported the Swabian family of the Hohenstaufen (which included Frederick Barbarossa, emperor 1155-90 and his son Henry VI r.1191-97), while the Danes favoured the Welfs, to whom they were related.
Not only was the country closely involved in European politics but Ingeborg herself was rather coveted on the marriage market and had received proposals from both the Welfs and the Hohenstaufens.
The union could give him political advantages, both against the Angevins and the Welfs. Philip was moreover subjected to the powerful persuasion by a circle of learned men.
Presumably Philip hoped to break the Danish support of the Welf party by the marriage.
Her treatment includes the royal lineages of the Carolingians, Robertians/Capetians, Welfs
, and Ottonians; a selection of countal houses, particularly from the Burgundian region with which she is most familiar; as well as another selection of Castellan families.