Q: 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.
This problem was compounded when the main Hanoverian army under Cumberland was defeated at the Battle of Hastenbeck and forced to surrender entirely at the Convention of Klosterzeven following a French Invasion of Hanover. The Convention removed Hanover and Brunswick from the war, leaving the Western approach to Prussian territory extremely vulnerable. Frederick sent urgent requests to Britain for more substantial assistance, as he was now without any outside military support for his forces in Germany.
A:
What Hanoverian leader lost the Battle of Hastenbeck?