The early Roman Republic (509–264 BCE) and the preceding regal period (753–509 BCE) are the most poorly documented periods of Roman history. Historical writing in Rome did not begin until the late 3rd century BCE, when Rome had already completed its conquest of Italy, established itself as a major power of the ancient world, and became involved in a gigantic struggle with Carthage for control of the western Mediterranean. The earliest Roman histories were brief résumés of facts and stories, but gradually historians embellished the sparse factual material (such as the list of annual magistrates from the beginning of the republic onward, religious records, and the texts of some laws and treaties) with both native and Greek folklore. Consequently, over time, historical facts about early Rome suffered from patriotic reinterpretation involving exaggerations of the truth, the suppression of embarrassing facts, and invention.
Ancient Roman historians initially differed over the precise date of Rome’s foundation. By the end of the republic, however, it was generally accepted that Rome had been founded in 753 BCE and that the republic had begun in 509 BCE, following the overthrow of Lucius Tarquinius Superbus, the last of Rome’s seven kings. According to tradition, the first six kings had been benevolent rulers, but the last was a cruel tyrant who was overthrown by a popular uprising.

How do you think historians guessed when Rome was founded?