ancient Romans were certain of the day Rome was founded: April 21, the day of the festival sacred to Pales, goddess of shepherds, on which date they celebrated the Par ilia (or Palilia). However, they did not know, or they were uncertain of, the exact year the city had been founded; this is one reason they preferred to date their years by the presiding consuls rather than using the formula A.U.C. or Ab urbe condita. Several dates had been proposed by ancient authorities, and Dionysius of Halicarnassus records these: The Greek historian Timaeus, one of the first to write a history to include the Romans, stated that Rome was founded in the 38th year prior to the first Olympiad, or 814/3 BC; Quintus Fabius Pictor, the first Roman to write the history of his people, in Greek, stated Rome was founded in the first year of the eighth Olympiad, or 748/7 BC; Lucius Cincius Alimentus claimed Rome was founded in the fourth year of the twelfth Olympiad, or 729/8 BC; and Cato the Elder calculated that Rome was founded 432 years after the Trojan War, which Dionysius states was equivalent to the first year of the seventh Olympiad, or 752/1 BC. Dionysius himself provided calculations showing that Rome was founded in 751 BC, starting with the Battle of the Allia, which he dated to the first year of the ninety-eighth Olympiad, 388/7 BC, then added 120 years to reach the date of the first consuls, Junius Brutus and Tarquinius Collatinus, 508/7 BC, then added the combined total of the reigns of the Kings of Rome (244 years) to arrive at his own date, 751 BC. Even the official Fasti Capitolini offers its own date, 752 BC. The most familiar date given for the foundation of Rome, 753 BC, was derived by the Roman antiquarian Titus Pomponius Atticus, and adopted by Marcus Terentius Varro, having become part of what has come to be known as the Varronian chronology. An anecdote in Plutarch where the astrologer Lucius Tarrutius of Firmum provides an argument based on a non-existent eclipse and other erroneous astronomical details that Rome was founded in 753 BC suggests that this had become the most commonly accepted date. Through its use by the third-century writer Censorinus, whose De Die Natali was the ultimate influence of Joseph Justus Scaliger's work to establish a scientific basis of ancient chronology, it became familiar.