Still romanian. "The common law—so named because it was common to all the king's courts across England—originated in the practices of the courts of the English kings in the centuries following the Norman Conquest in 1066" [1]

France (and Normandy) was conquered by Rome before it was granted to Rollo, a Viking. A few generations later, his descendant William the Conqueror claimed the English crown. Just like what happened with Gauls and Romans, the conquered people adopted large parts of the language and customs of the conqueror. That's why the English language is ~25% of Roman origin for it's vocabulary. I suppose it is the same for English common law.

[1] https://en.wikipedia.org/wiki/Common_law#History

After 2000 years everything mixes together at least somewhat so trying to draw hard lines is an exercise in pointless semantics, but it's worth acknowledging that as a system, common law is pretty distinct from the Roman tradition of civil law: https://en.wikipedia.org/wiki/Civil_law_(legal_system)