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.

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.
In what year did Christian troops lose control of Valencia?

From the years 1500 to 1850, an estimated 3.5 million captives were forcibly shipped from West/Central Africa to Brazil; the territory received the highest number of slaves of any country in the Americas. Scholars estimate that more than half of the Brazilian population is at least in part descended from these individuals. Brazil has the largest population of Afro-descendants outside of Africa. In contrast to the US, during the slavery period and after, the Portuguese colonial government and later Brazilian government did not pass formal anti-miscegenation or segregation laws. As in other Latin countries, intermarriage was prevalent during the colonial period and continued afterward. In addition, people of mixed race (pardo) often tended to marry white, and their descendants became accepted as white. As a result, some of the European descended population also has West African or Amerindian blood. According to the last census of the 20th century, in which Brazilians could choose from five color/ethnic categories with which they identified, 54% of individuals identified as white, 6.2% identified as black, and 39.5% identified as pardo (brown) — a broad multi-racial category, including tri-racial persons.
How many slaves were shipped from Africa to Brazil between 1500 and 1850?

By 16:50, with the Prussian southern attacks in danger of breaking up, the Prussian 3rd Guards Infantry Brigade of the Second Army opened an attack against the French positions at St. Privat which were commanded by General Canrobert. At 17:15, the Prussian 4th Guards Infantry Brigade joined the advance followed at 17:45 by the Prussian 1st Guards Infantry Brigade. All of the Prussian Guard attacks were pinned down by lethal French gunfire from the rifle pits and trenches. At 18:15 the Prussian 2nd Guards Infantry Brigade, the last of the 1st Guards Infantry Division, was committed to the attack on St. Privat while Steinmetz committed the last of the reserves of the First Army across the Mance Ravine. By 18:30, a considerable portion of the VII and VIII Corps disengaged from the fighting and withdrew towards the Prussian positions at Rezonville.

By late afternoon, what were the Prussian southern attacks at risk of?