On 22 August, Charles raised his royal standard in Nottingham, effectively declaring war on Parliament. The two sides continued to recruit; Parliament positioned its main field army, commanded by the Earl of Essex, between the King and London, in Northampton. Charles was heavily outnumbered at this stage; he fielded between a quarter and half as many men as Essex's 20,000, and those he did have were not so well equipped. Despite this, Essex did not press his advantage: possibly because his orders allowed him to present the King with a petition to peacefully submit to Parliament, as an alternative to military action. Although there had been small-scale fighting, particularly in northern and south-western England, the two field armies did not significantly manoeuvre against each other until mid-September. On 13 September, Charles moved his army west through Derby and Stafford towards Shrewsbury, where he hoped to be reinforced by the Royalist regiments being raised in Wales and the north-west and south-west of England.