Civil law is indeed heavily inspired by Roman Law. After the Fall of the Roman Empire, it survived thanks to the continued presence of the Catholic Church and its influence on law-making during the Middle Ages. During these times, civil law saw an expansion and development under the influence of ecclesiastic Canon law. It also continued existing during the Byzantine Empire up until the 15th century. When that Empire fell, its scholars would free and spread its principles all over Western Europe. It was a source of inspiration for laws when common laws proved insufficient on some cases and situations. Its influence started to be greater and greater and it finally became the main source of law for most European countries though adapted to their particular national contexts. It was codified by Germanic scholars and also underwent even more codification and development during the Enlightenment Period. It has been adopted by most countries in Continental Europe whereas in the United Kingdom, it is Common Law that prevails as the source of legislation. Even Japan, during the Meiji period decided to use it as the source of its modern legal system (mainly inspired by the legal systems of France and Germany).
