By 18 September, Rupert's force had caught up to the Parliamentarians outside Aldbourne. Essex had lost his advantage; Parliamentarian intelligence reports had convinced him that Charles was heading towards Oxford and had given up the campaign. In fact Charles was barely away, but the complacency such reports induced meant that one contemporary source stated the Parliamentarians were marching barely a day, allowing the Royalists to quickly catch up. Suitably chastened by the discovery of his error, Essex increased the pace of his retreat, with the Royalists pursuing closely. Both sides were heading for Newbury, on roughly parallel routes; the Royalists' route took them through Faringdon and Wantage, increasing the distance they would have to travel to while the Parliamentarians had to travel only 20. Charles reacted by dispatching Rupert and 7,000 cavalry in a flying column to disrupt and harass the Parliamentary retreat. Encountering Essex's forces at Aldbourne Chase, Rupert made battle; however, lacking enough troops to engage the Parliamentarians directly, he instead attacked a section of their army, causing chaos and crucially delaying Essex's march just enough for Charles's forces to close the gap.