1) Why was Rome significant in the history of Western civilization?
Rome was significant in multiple different aspects of the history of western civilization. Roman literature, drama, law, art, architecture were all very influential throughout history.
One of the most significant impacts of the Romans, was that they took interest in Greek culture and made efforts to preserve it. Without this preservation, the modern world would be unable to have any insight into Greek civilization. Roman culture actually mirrors Greek culture in multiple aspects. Early Roman religion is very similar to that of Greek religion.
Rome was the first civilization that enforced the idea of natural law, which is now enforced in western civilization. This was the idea of a single standard of justice that every individual is subject to. Prior to this, the judicial system was confusing and chaotic; this idea of natural solved the problem and made the laws well known.
Multiple Roman architectural and engineering vices are similar to what we see today. Roads, bridges, aqueducts, dams, as well as buildings, are very similar to what we see in the modern world. Rome had the finest quality, and workmanship, that have held up for centuries.
Roman literature was very influential. The uses of rhetoric by Roman figures are foundational in the world of rhetoric. The Latin language, itself, had an impact. Many languages are derived from Latin, and more than half of the English language actually comes from the Latin language of the Romans.
2) What was the significance of St. Augustine in Christian history?
St. Augustine of Hippo (354-430) was an early Christian theologian and philosopher. His writings and teaching significantly impacted Christian history. He was not always a devout Christian, he was born to a Christian mother, but he was far from being considered a Christian in his early years. He was a smart man, and he sought fulfillment and explanation. He encountered many philosophical and theological controversies. He invested a lot of thought, and eventually came to believe that Christianity was the truth.
He wrote a lot of documents, including his own autobiography that impacted Christianity and also western civilization. He explained things to help Christians further understand their beliefs, and he explained to pagans who did not understand the concept of Christianity. Without his contributions, there may have been more Christian persecutions, and Christians themselves may not have found the teachings and understandings that St. Augustine concluded.