THE IMPERIAL TIMES
DCCXLI A.V.C

EMPEROR'S STEPSON DIVORCES WIFE
TO MARRY MOTHER-IN-LAW/STEP-SISTER
-EXPERTS SAY CONFUSING, BUT NOT INCESTUOUS

Old Claudius relates that Tiberius divorced his wife to marry the widow Julia. This is supported by the ancient sources. Velleius states that Tiberius married Julia, with no mention of his divorce. Suetonius provides the best evidence for Tiberius' reluctancy, but does not mention who forced him. Dio, however, says that Augustus reluctantly made Tiberius his right-hand man and forced him to divorce his wife to marry Julia. In essence Tiberius was designated next in line, since Julia's sons were too young. In his treatment of this affair, Graves faithfully follows Suetonius. Both Suetonius and Graves focus on Julia's libidinous overtures toward Tiberius, his disgust at her and his deep affection for Vipsania. None of the ancient authors include Livia as the force behind this power marriage. Graves can't resist making her the (step)mother of all evil.
At any rate Tiberius is A) a gutless wonder who can't say no to mommy; B) an ambitious S.O.B.; C) an idiot; D) all of the above. The answer is D.