Petty treason was essentially an aggravated form of murder. It consisted of:
The element of betrayal is the reason why this crime was considered worse than an ordinary murder; medieval and post-medieval society rested on a framework in which each person had his or her appointed place and such murders were seen as threatening this framework. Many people had somebody subordinate to them and feared the consequences if the murder of superiors was not punished harshly. While the penalty for murder was simply hanging, a man convicted of treason was hanged, drawn and quartered.
The most common form of petty treason was a wife murdering her husband and, up until the abolition of this form of punishment, husband-murderers were burned at the stake. The law offered a modicum of mercy to women who were to be executed in this fashion: the executioner was equipped with a cord passed around the victim's throat and, standing outside of the fire, would pull it tight, strangling her before the flames could reach her. In a few instances, things went wrong, with the cord burning through and the victim burning alive; the ensuing scandals were part of what led to the abolition of this punishment and its substitution by hanging in 1790.
However, the rules of evidence in treason trials were more strict than in murder trials, making it easier to be acquitted. (See the Treason Act 1695 for full details.)
The common law offence was codified in the Treason Act 1351.