Cassi, the inhabitants of Hertfordshire or Cassio.—Cæsar, Commentaries.
Cassib'ellaun or Cassib'elan (probably "Caswallon"), brother and successor of Lud. He was king of Britain when Julius Cæsar invaded the island. Geoffrey of Monmouth says, in his British History, that Cassibellaun routed Cæsar, and drove him back to Gaul (bk. iv. 3, 5). In Cæsar's second invasion, the British again vanquished him (ch. 7), and "sacrificed to their gods as a thank-offering 40,000 cows, 100,000 sheep, 30,000 wild beasts, and fowls without number" (ch. 8). Androg'eus (4 syl.) "duke of Trinovantum," with 5000 men, having joined the Roman forces, Cassibellaun was worsted, and agreed "to pay 3000 pounds of silver yearly in tribute to Rome." Seven years after this Cassibellaun died and was buried at York.
In Shakespeare's Cymbeline the name is called "Cassibelan."
Polyænus of Macedon tells us that Cæsar had a huge elephant armed with scales of iron, with a tower on its back, filled with archers and slingers. When this beast entered the sea, Cassivelaunus and the Britons, who had never seen an elephant, were terrified, and their horses fled in affright, so that the Romans were able to land without molestation.—Drayton, Polyolbion, viii.
There the hive of Roman liars worship a gluttonous emperor-idiot.
Such is Rome ... hear it, spirit of Cassivelaun.
Tennyson,
Boadicea
.