Abstract
Based on the evidence available in chronicles and documents of Middle-Ages’ Moldavia, we have analyzed, compared and explained the significance of the terms treason and high treason. The initial meaning of the boyars’ disloyalty towards the reigning prince and, respectively of infidelity towards the Ottoman Porte throughout the entire medieval period was preserved. Likewise, there was no confusion between treason and high treason, their significance was profoundly known and used carefully. This shows that the vow between the ruler and the boyars was kept until the end of the age, even if it overlapped with that towards the sultan.