You will be given a context, a subject and a relation. Your task is to generate a question based on the subject and relation. The generated question should include the given subject. Try to use a minimum number of words that are not present in either context, subject or relation while generating question.
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Question: Context : After Attila's death in 453 AD, his Empire crumbled and its remains were ruled by his three sons, Ellac, Dengizich and Ernak. 
Subject : Ellac 
Relation : date of death

Answer: On what date did Ellac die?


Question: Context : The Yorkshire Mounted Brigade was a formation of the Territorial Force of the British Army, organised in 1908. 
Subject : Yorkshire Mounted Brigade 
Relation : military branch

Answer: What army did Yorkshire Mounted Brigade serve in?


Question: Context : Iron Dome (Hebrew: כִּפַּת בַּרְזֶל, kippat barzel) is a mobile all-weather air defense system developed by Rafael Advanced Defense Systems and Israel Aircraft Industries. 
Subject : Iron Dome 
Relation : service entry

Answer:
What year was Iron Dome made?