Suetonius: The Horse Incitatus
o prevent Incitatus, his favourite horse, from growing restive he always picketed the neighbour-hood with troops on the day before the races, ordering them to enforce absolute silence. Incitatus owned a marble stable, an ivory stall, and a jewelled collar; also a house, furniture, and slaves - to provide suitable entertainment for guests whom Caligula invited in its name. It is said that he even planned to award Incitatus a consulship.
Suetonius: Caligula 55
Cassius Dio: The Horse Incitatus
One of the horses, which he named Incitatus, he used to invite to dinner, where he would offer him golden barley and drink his health in wine from golden goblets; he swore by the animal's life and fortune and even promised to appoint him consul, a promise that he would certainly have carried out if he had lived longer.
Cassius Dio: Book 69