Complex sentence: As depicted by Marsh, Alleyn's family is similar to that created by Sayers for her Wimsey, in that Alleyn has a titled older brother, who however is much less grand (merely a baronet rather than a duke).
Split into simpler sentences: As depicted by Marsh, Alleyn's family is similar to that created by Sayers for her Wimsey. Like Wimsey, Alleyn has a titled older brother, who however is much less grand (merely a baronet rather than a duke).