Complex sentence: Franz Karl was an unambitious and generally ineffectual man, although he was a member of the Council that ruled in the stead of his mentally retarded brother Emperor Ferdinand from 1835 to 1848.
Split into simpler sentences: Franz Karl was an unambitious and generally ineffectual man. Although part of the Council that ruled in the stead of his mentally retarded brother Emperor Ferdinand from 1835 to 1848.