Definition: In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.
Input: Passage: The Abbasid Caliphate, founded by Abu al-‘Abbās ‘Abdu'llāh ibn Muhammad as-Saffāḥ, the great-great-grandson of Muhammad's uncle Abbas, in 749, had ruled northeastern Africa, Arabia, and the Near East, even though their rule had by 1258 shrunk to only southern and central Iraq. The Abbasids' seat of power for almost 500 years was Baghdad, a city considered to be the jewel of Islam and one of the largest and most powerful cities in the world. But under attack from the Mongols, the city fell on February 15, 1258, a loss often considered in the Muslim world as the single most catastrophic event in the history of Islam, the end of the Islamic Golden Age. The Christian Georgians had been the first to breach the walls, and as described by historian Steven Runciman, "were particularly fierce in their destruction". When Hulagu conquered the city, the Mongols demolished buildings, burned entire neighborhoods, and massacred nearly all the men, women, and children. But at the intervention of Doquz Khatun, the Christian inhabitants were spared.
For Asiatic Christians, the fall of Baghdad was cause for celebration. Hulagu and his Christian queen came to be considered as God's agents against the enemies of Christianity, and were compared to the influential 4th-century Christian Emperor Constantine the Great and his revered empress mother, Saint Helen, an icon of the Christian church. The Armenian historian Kyrakos of Gandzak praised the Mongol royal couple in texts for the Armenian Church, and Bar Hebraeus, a bishop of the Syriac Orthodox Church, also referred to them as a Constantine and Helena, writing of Hulagu that nothing could compare to the "king of kings" in "wisdom, high-mindedness, and splendid deeds".
Output:
What were the full names of the two people Hulagu and his Christian queen were compared to?