This paper examines the 1794 Treason Trials as a turning point in the definition of treason in Britain, influenced by the fluctuating English constitution and the impact of the French Revolution. As a country without a written constitution, British state power relied on a carefully balanced relationship between the king, Parliament, and the people. The definition of treason, however, identified state power as residing solely in the person of the king; threats to the people or to Parliament were not explicitly stated as attacks on the state. Prior to 1789, the same was true of France. However, the French Revolution overturned these structures in an attempt to redefine government according to the rights of the people. Initially, British response to the French Revolution was positive, seeing it as an attempt to mimic the British model of mixed government. Reform societies, especially, took inspiration from the French model and attempted to introduce measures of reform for Parliament. As the French Revolution progressed, those in power in England increasingly saw the violent revolution as a threat to stability in England. Out of a fear that reform societies sympathies with France might lead to a similar violent revolt against the English government, Prime Minister William Pitt and his attorney-general John Scott brought the leaders of the reform movement to trial for treason. Ultimately, the defense, led by Thomas Erskine, was able to prove that the reformers attempts to reform Parliament in no way represented an attack on the person of the king and therefore did not qualify as treason. The acquittal of the defendants led directly to new legislation which redefined treason to include attacks or threats to Parliament, acknowledging that state power had shifted beyond the king.