Twelve Caesars (c1596). De vita Caesarum, commonly known as The Twelve Caesars, is a set of twelve biographies of Julius Caesar and the first 11 emperors of the Roman Empire written by Gaius Suetonius Tranquillus. The work, written in AD 121 during the reign of the emperor Hadrian, was the most popular work of Suetonius, at that time Hadrian's personal secretary, and is the largest among his surviving writings. It was dedicated to a friend, the Praetorian prefect Gaius Septicius Clarus. The Twelve Caesars was considered very significant in antiquity and remains a primary source on Roman history. The book discusses the significant and critical period of the Principate from the end of the Republic to the reign of Domitian; comparisons are often made with Tacitus, whose surviving works document a similar period. The book can be described as racy, packed with gossip, drama, and sometimes humour. At times the author subjectively expresses his opinion and knowledge. Although he was never a senator himself, Suetonius took the side of the Senate in most conflicts with the princeps, as well as the senators' views of the emperor. That resulted in biases, both conscious and unconscious. Suetonius lost access to the official archives shortly after beginning his work. He was forced to rely on secondhand accounts when it came to Claudius and does not quote the emperor. The book still provides valuable information on the heritage, personal habits, physical appearance, lives, and political careers of the first Roman emperors. It mentions details which other sources do not. For example, Suetonius is the main source on the lives of Caligula, his uncle Claudius, and the heritage of Vespasian. Suetonius made a reference in this work to Chrestus, which could refer to Christ. During the book on Nero, Suetonius does mention Christians. As with many of his contemporaries, Suetonius took omens seriously and carefully includes reports of omens portending imperial births, accessions, and deaths. The first few chapters of this section are missing. Suetonius begins this section by describing Caesar's conquests, especially in Gaul, and his Civil War against Pompey the Great. Several times Suetonius quotes Caesar. Suetonius includes Caesar's famous decree, Veni, vidi, vici. In discussing Caesar's war against Pompey the Great, Suetonius quotes Caesar during a battle that Caesar nearly lost, That man does not know how to win a war. Suetonius describes an incident that would become one of the most memorable of the entire book. Caesar was captured by pirates in the Mediterranean Sea. Caesar engaged in debate and in philosophical discussion with the pirates while in captivity. He also promised that one day he would find them and crucify them. When told by the pirates that he would be held for a ransom of 20 talents of gold, Caesar laughed, and said that he must be worth at least 50 talents. Just as he had promised, after being released, Caesar captured the pirates and crucified them. It is from Suetonius that we first learn of another incident during the life of Julius Caesar. While serving as quaestor in Hispania, Caesar once visited a statue of Alexander the Great. Upon viewing this statue, Suetonius reports that Caesar fell to his knees, weeping. When asked what was wrong, Caesar sighed, and said that by the time Alexander was his age, Alexander had conquered the whole world. Suetonius describes Caesar's gift at winning the loyalty and admiration of his soldiers. Suetonius mentions that Caesar commonly referred to them as comrades instead of soldiers. When one of Caesar's legions took heavy losses in a battle, Caesar vowed not to trim his beard or hair until he had avenged the deaths of his soldiers. Suetonius describes an incident during a naval battle. One of Caesar's soldiers had his hand cut off. Despite the injury, this soldier still managed to board an enemy ship and subdue its crew. Suetonius mentions Caesar's famous crossing of the Rubicon, on his way to Rome to start a Civil War against Pompey and ultimately seize power. Suetonius later describes Caesar's major reforms upon defeating Pompey and seizing power. One such reform was the modification of the Roman calendar. The calendar at the time had already used the same system of solar years and lunar months that our current calendar uses. Caesar updated the calendar so as to minimize the number of lost days due to the prior calendar's imprecision regarding the exact amount of time in a solar year. Caesar also renamed the fifth month in the Roman calendar July, in his honor. Suetonius says that Caesar had planned on invading and conquering the Parthian Empire. These plans were not carried out due to Caesar's assassination.