Task: Text Categorization
Input (English): This ruler asked for assistance from Gregory XIII to intercede in an unsuccessful conflict known as the Livonian War. This ruler divided his kingdom into two realms, one of which was not ruled by him called the zemschina. The other portion was governed by the oprichniki, who dressed in black and terrorized the countryside. This ruler was the first to take the title of (*) tsar. This man contributed to the decline of the Rurikid dynasty by killing his heir. For 10 points, name this tsar whose reign included a considerable amount of violence.
Output (English): History