instruction:
This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
question:
The city remained in the hands of Christian troops until 1102, when the Almoravids retook the city and restored the Muslim religion. Although the self-styled 'Emperor of All Spain', Alfonso VI of León and Castile, drove them from the city, he was not strong enough to hold it. The Christians set it afire before abandoning it, and the Almoravid Masdali took possession on 5 May 1109. The event was commemorated in a poem by Ibn Khafaja in which he thanked Yusuf ibn Tashfin for the city's liberation.The declining power of the Almoravids coincided with the rise of a new dynasty in North Africa, the Almohads, who seized control of the peninsula from the year 1145, although their entry into Valencia was deterred by Ibn Mardanis, King of Valencia and Murcia until 1171, at which time the city finally fell to the North Africans. The two Muslim dynasties would rule Valencia for more than a century.
answer:
In what year did Christian troops lose control of Valencia?


question:
The roots of Presbyterianism lie in the European Reformation of the 16th century; the example of John Calvin's Geneva being particularly influential. Most Reformed churches which trace their history back to Scotland are either presbyterian or congregationalist in government. In the twentieth century, some Presbyterians played an important role in the ecumenical movement, including the World Council of Churches. Many Presbyterian denominations have found ways of working together with other Reformed denominations and Christians of other traditions, especially in the World Communion of Reformed Churches. Some Presbyterian churches have entered into unions with other churches, such as Congregationalists, Lutherans, Anglicans, and Methodists. Presbyterians in the United States came largely from Scotch-Irish immigrants communities, and also from New England Yankee communities that had originally been Congregational but changed because of an agreed-upon "Plan of Union of 1801" for frontier areas.
answer:
Where do most presbyterian churches trace their history back to?


question:
In February 1974, the British Prime Minister, Edward Heath, advised the Queen to call a general election in the middle of her tour of the Austronesian Pacific Rim, requiring her to fly back to Britain. The election resulted in a hung parliament; Heath's Conservatives were not the largest party, but could stay in office if they formed a coalition with the Liberals. Heath only resigned when discussions on forming a coalition foundered, after which the Queen asked the Leader of the Opposition, Labour's Harold Wilson, to form a government.
answer:
When did Edward Heath ask Elizabeth to call a general election?