The main legacies of the Romans are religion, the alphabet, language, law and art.
Christianity developed from a religion among a small group of Jews (who lived in Judea, which was part of the Roman Empire) into a mass religion in the Roman days. It spread around the Roman Empire. It became the religion of the masses and then state religion. Catholic Christianity and Orthodox Christianity developed during the Late Roman Empire. They were originally called Latin or Western Christianity and Greek or Eastern Christianity respectively. The former was the main religion in the western part of the Roman Empire and the latter was the main religion in the eastern part of the Roman Empire.
Western European languages have adopted and adapted the Latin alphabet. The only letters in the English language which do not come from the Latin alphabet are J, U and W.
Italian, French, Spanish, Portuguese, and Romanian are languages derived from Latin (romance languages). Many Latin words have entered English via two routes. One was that Latin was the language of the church in the Middle Ages. The other was the Norman conquest of England. French became the court language and many French words entered into the English language. These words are usually of Latin origin.
Many international words in medicine, law and theology are Latin.
The key principles of Roman civil law have provided the foundation or an inspiration for the law of many modern countries. These are: citizenship status and citizenship rights, equality under the law, the right to have a proper trial and to defend oneself, the right to appeal, that the burden of proof rests on the accuser and not on the accused, that it is the exact form of actions and not intentions or words which is punishable, and that a law deemed unreasonable or unfair can be repealed.
The Romans influenced European architecture, sculpture and painting until the early 20th century. They influenced the art of the Renaissance (14th-15th century) Baroque (17th-18th century) and Neoclassicism (18th-20th century, and is still sometimes used today). Palladian architecture was also based on Roman architecture. It was popular from the 17th century to the 20th century and was often used for public buildings. Latin literature was very influential in European literature until the mid-20th century.