Task: Question Generation
Input (English): Context : The Battle of Sahagún (21 December 1808) was a cavalry clash at Sahagún, Spain, in which the British 15th Light Dragoons (Hussars) defeated two regiments of French cavalry during the Corunna Campaign of the Peninsular War. 
Subject : Battle of Sahagún 
Relation : point in time
Output (English): When did Battle of Sahagún occurr?