Medievalist architectural historian whose influential book on architectural type significance and reception influenced post-war generation of medievalists. Bandmann grew up in Essen. He studied art history at the University in Cologne, inspired by the modern art which had been at the Folkwang Museum there until purged by the Nazis in 1933. Bandmann's dissertation written under Hans Kauffmann in 1942 focused on the abbey church of Essen-Werden.

Hoeltje was born to Edmund Hoeltje, a professor and director of a mechanical engineering institute.  His family moved from Hannover to Hagen and later Essen both where he attended schools.