Complex sentence: Sex, Power, and Politics in the Early Empire, p.78 to her possible brother Marcus Valerius Messala Corvinus; second cousin to the children of Messalina, Claudia Octavia and Britannicus.
Split into simpler sentences: Sex, Power, and Politics in the Early Empire, p.78. Varus the younger was a generation removed from the children of Messalina, Claudia Octavia and Britannicus.