Page 127 of Now I Rise (The Conqueror's Saga 2)

trebuchet: A medieval engine of war with a sling for hurling large stones

vaivode: Warlord prince of Wallachia

vassal state: A country allowed to retain rulership but subject to the Ottoman Empire, with taxes of both money and slaves for the army

vizier: A high-ranking official, usually advisor to the sultan

Wallachia: A vassal state of the Ottoman Empire, bordered by Transylvania, Hungary, and Moldavia

Source: www.allfreenovel.com