The coroner began as a medieval tax guardian for the English crown
The word coroner shares its root with crown. In September 1194 England ordered every county to elect three knights and a clerk as keepers of the pleas of the crown, officials meant partly to watch royal revenues and check the power of sheriffs. Investigating unexpected deaths was only one part of the job.
Those early keepers held inquests on bodies found in their area, heard confessions from felons, and received the oaths of criminals who had fled to sanctuary and chose exile instead. None of these tasks was entirely new; local officials such as the hundred's bailiff had handled many of them, and for decades duties overlapped. Barons even pleaded with King John in 1215 that no sheriff should meddle with crown pleas without the coroners. Anyone who stumbled on a body after a sudden or unnatural death had to raise the hue and cry and alert the coroner. Edward I extended the office to Wales through the Statute of Rhuddlan in 1284.
Scotland went a different way. It had coroners from about 1400 until around 1800, then dropped them, and today suspicious deaths there go to the Procurator Fiscal on behalf of the Lord Advocate. In England and Wales a coroner is now a specialist judge, paid by local authorities but independent of them; dismissal needs both the Lord Chancellor and the Lord Chief Justice. The court can summon witnesses, and lying before it counts as perjury.
The remit is deliberately narrow: who died, and how, when and where. Most deaths never reach a coroner. If a doctor saw the person within 14 days of death, that doctor can usually sign the certificate. Coroners step in when nobody medical can explain the death, or when it was violent, unnatural, caused by poisoning or industrial injury, or happened in police custody or prison. They do not assign civil or criminal blame.
Former British territories adapted the idea. Canada has no national system, so each province chooses: Alberta, Manitoba, Nova Scotia, and Newfoundland and Labrador use medical examiners, a US-born model just over a century old, while Ontario and Prince Edward Island require their coroners to be physicians. Every Australian coroner is a legally trained magistrate, and in Brazil the work falls to police officers with medical degrees.
Source: Coroner