Task: Question Answering
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. 
Question : When did Battle of Sahagún occurr?
Output (English): 21 December 1808