The rebellion was led by Charles Neville, 6th Earl of Westmorland, and Thomas Percy, 7th Earl of Northumberland, who in November 1569 occupied Durham. Thomas Plumtree celebrated Mass in Durham Cathedral. From Durham, the rebels marched south to Bramham Moor, while Elizabeth struggled to raise forces sufficient to confront them. But, hearing of a large force being raised by the Earl of Sussex, the rebels abandoned plans to besiege York, and captured Barnard Castle instead. They proceeded to Clifford Moor, but found little popular support. Sussex marched out from York on 13 December 1569 with 7,000 men against the rebels' 4,500, and was followed by 12,000 men under Baron Clinton. The rebel earls retreated northward and finally dispersed their forces, fleeing into Scotland.
Question: How many more men did Sussex have on December 13,1569 than the rebels did?
Answer: 2500