 By the end of the thirteenth century , several offences against either one 's lord , or one 's king , were treasonable . High treason , defined as transgressions against the sovereign , was first codified during King Edward III 's reign by the Treason Act 1351 . It clarified exactly what crimes constituted treason , following earlier , somewhat " over zealous " interpretations of England 's legal codes . For instance , high treason could be committed by anyone found to be compassing the king 's death or counterfeiting his coin . High treason remained distinct though , from what became known as petty treason : the killing of a lawful superior , such as a husband by his wife . Though twelfth century contemporary authors made few attempts to differentiate between high treason and petty treason , enhanced punishments may indicate that the latter was treated more seriously than an ordinary felony . 
 By the end of the thirteenth century , several offences against either one <a href='null_genetive' title='1'><mark>'s</mark></a>lord , or one <a href='null_genetive' title='2'><mark>'s</mark></a>king , <a href='uninflect' title='3'><mark>were</mark></a> treasonable . High treason , defined as transgressions against the sovereign , was first codified during King Edward III <a href='null_genetive' title='4'><mark>'s</mark></a>reign by the Treason Act 1351 . It clarified exactly what crimes constituted treason , following earlier , somewhat " over zealous " interpretations of England <a href='null_genetive' title='5'><mark>'s</mark></a>legal codes . For instance , high treason could be committed by anyone found to be compassing the king <a href='null_genetive' title='6'><mark>'s</mark></a>death or counterfeiting his coin . High treason remained distinct though , from what became known as petty treason : the killing of a lawful superior , such as a husband by his wife . Though twelfth century contemporary authors made few attempts to differentiate between high treason and petty treason , enhanced punishments may indicate that the latter was treated more seriously than an ordinary felony . 
By the end of da thirteenth century , several offences against either one  lord , or one  king , was treasonable . High treason , defined as transgressions against the sovereign , was first codified durin King Edward III  reign by tdaTreason Act 1351 . It clarified exactly what crimes constituted treason , following earlier , somewhat " ova zealous " interpretations of England  legal codes . fa instance , high treason could b committed by any1 found to be compassing the king  death or counterfeiting his coin . High treason remained distinct though , from wht became known as petty treason : the killing of a lawful superior , such as a husband by his wife . Though twelfth century contemporary authors made few attempts to differentiate between high treason and petty treason , enhanced punishments may indicate dat the latter was treated more seriously than an ordinary felony .