During the last three years of the Emperor’s life Caligula rapidly advanced in his favour. He was formally adopted, and was continually named as the Emperor’s heir along with the young Tiberius. The adviser and friend of Caligula at this time was the Jewish prince Agrippa, the half-brother of Herodias, the incestuous wife of Herod Antipas, and grandson of Herod the Great. The election of Caligula as successor to Tiberius is a somewhat puzzling circumstance. Tacitus says that he always showed signs of insanity, but at the same time credits him with great astuteness in winning the old man’s favour. It is more probable, from other accounts, that the madness of Caligula was the result of an illness to which he fell a victim almost immediately after his succession, for that he was technically mad is undeniable. We have a curious picture of him from the pen of Philo the Jew, who arrived from Alexandria with a deputation of Jews to protest against being required to worship Caligula exclusively as a god. The envoys found Caligula superintending the building of one of his palaces at Baiæ. They were introduced to the half-finished edifice, where the Emperor was hurrying from one room to another, feverishly running up and down stairs. He suddenly observed his visitors, and remarking, “So you are those atheists,” vanished; presently he reappeared, and after saying “Why don’t you eat pork?” finally disappeared. It is not likely that Tiberius would have entrusted the fate of the civilized world to a man whose intellect was so obviously disturbed. If, however, we ask who had an interest in the succession of Caligula, the answer is, Agrippa, who, according to Josephus, had found men to finance him in order that he might push his fortunes at Rome. In this he had been somewhat imprudent, and an impatient remark he made to Caligula was reported to Tiberius, who put him under guard for the rest of his reign; on the death of Tiberius he exchanged captivity for the throne of Herod the Great. There is a story that Tiberius, being in doubt as to whether he should nominate his own grandson, the younger Tiberius, or his adopted son Caligula, consulted his diviners, who told him to appoint the one of the two children who should first enter the room after both had been summoned; the Emperor fell in with the suggestion, and the parties interested then contrived that Caligula should be the first to arrive.