King Edward I, following his conquest of Wales, issues the Statute of Rhuddlan (or Statute of Wales) on March 3, 1284. The statue was promulgated on March 19, 1284; formally incorporated the Principality of North Wales into the English Crown.
The statue, promulgated on March 19, 1284, established English administration and common law and introduced the shire system, basically ending Welsh independence. Full legal integration into England didn't occur until the Laws in Wales Acts 1535-1542 when Wales was fully incorporated into the Kingdom of England, creating the unified realm existing today.