How did civil law develop?

There are two meanings for 'civil law'.

'Civil Law', also called Roman Law, is a system of codified law that developed from an ancient Roman Law code known as the Code of Justinian. The concept eventually spread to other countries as they adopted their own Civil Law Codes. A Civil Law system has a written code of law that covers civil and criminal matters and that all judges must follow. Civil Law codes are used in most countries in Europe and South America, and some parts of Africa and Asia. Those codes have been modified and modernized by their respective governing bodies at various times. The Napoleonic Code adopted by France in 1804 is an example.

Countries that use the Civil Law legal tradition stand in contrast to those that use a Common Law legal tradition, which is based on English Common Law. Common Law relies on prior judicial decisions that have been made in similar cases. Those prior decisions are referred to as case law or precedent and must be followed in all subsequent similar cases. That tradition gives judges an important role in shaping law in England and America.

Common Law traditions also have codified law. Many principles from Common Law have been codified in both criminal and civil law codes.

As for the second meaning of civil law, the term 'civil law' is used to distinguish legal actions that deal with civil relationships such as marriage, contracts, creditors, disputes between neighbors, etc., in contrast to criminal law. It developed from disputes between people in which a judge (or local nobleman) listened to the parties and rendered an opinion as to who was at fault and the amount of damages that would be awarded.
There are two meanings for 'civil law'.

'Civil Law', also called Roman Law, is a system of codified law that developed from an ancient Roman Law code known as the Code of Justinian. The concept eventually spread to other countries as they adopted their own Civil Law Codes. A Civil Law system has a written code of law that covers civil and criminal matters and that all judges must follow. Civil Law codes are used in most countries in Europe and South America, and some parts of Africa and Asia. Those codes have been modified and modernized by their respective governing bodies at various times. The Napoleonic Code adopted by France in 1804 is an example.

Countries that use the Civil Law legal tradition stand in contrast to those that use a Common Law legal tradition, which is based on English Common Law. Common Law relies on prior judicial decisions that have been made in similar cases. Those prior decisions are referred to as case law or precedent and must be followed in all subsequent similar cases. That tradition gives judges an important role in shaping law in England and America.

Common Law traditions also have codified law. Many principles from Common Law have been codified in both criminal and civil law codes.

As for the second meaning of civil law, the term 'civil law' is used to distinguish legal actions that deal with civil relationships such as marriage, contracts, creditors, disputes between neighbors, etc., in contrast to criminal law. It developed from disputes between people in which a judge (or local nobleman) listened to the parties and rendered an opinion as to who was at fault and the amount of damages that would be awarded.