The financial reforms helped Parliament to recover from the setbacks suffered during 1642. Parliament now had a sound financial base which could also provide a springboard for future success. Meanwhile, Charles had relied on the gentry providing money to fund his war effort. The method wasn’t effective because the gentry’s money was finite. As the war wore on, the King started to run out of money and couldn’t afford to pay his soldiers. His soldiers pillaged from the local communities as a result of this. In due course, neutrals would tend to side with Parliament. This implies that in terms of finance Parliament had the upper hand which developed additional bonuses for them. However despite these reforms, Parliament still suffered setbacks, most notably the Battle of Lostwithiel during which the Earl of Essex lost 5,400 men. This had undone the victory at Marston Moor.
Another advantage enjoyed by Parliament was the formation a national war strategy. This was done through the Self-Denying Ordinance which forbade Members of Parliament from holding military commands. As a result, the War Party, under the leadership Lord Fairfax and Oliver Cromwell, took command of Parliamentary army; this meant that the army leaders had united aims (the Peace Party had wanted a negotiated settlement with the King which was the antithesis of the aims of the War Party). Therefore, the Earl of Essex and Earl of Manchester, who had been chosen for their noble status rather than military prowess, resigned their posts in the army (Cromwell had accused Essex of incompetence after the defeat at Lostwithiel). The prowess of the new leadership was witnessed at the Battle of Naseby after which Charles was not able to field a full army again. The King, on the other hand, was not able to separate rivalry between his subordinates (namely Rupert and Digby), and thus unable to enforce a national war strategy. This implies that parliament was able to form a national war strategy which allowed it to coordinate attacks on Royalist positions.
The third advantage which Parliament benefited from was the creation of the New Model Army. The army was regularly paid, loyal, professional and most importantly mobile. This mobility meant it could fight anywhere in the country, thus overcome the problem of localism (localism had been a problem which obstructed both sides at the beginning of the war). Charles wasn’t unable to implement a national war strategy and thus unable to move coordinate attacks on Parliament strongholds; demonstrated by the Earl of Newcastle’s failure to march south to attack London at the beginning of the war. Therefore, it would appear that the New Model Army gave Parliament the advantage in terms of its mobility and professionalism; Charles did not have such an army to deploy against Parliament.
It would appear that the Self-Denying Ordinance was the most important advantage enjoyed by Parliament during the First Civil War. The ordinance enabled to the “incompetent” generals such as the Earl of Manchester to lose their military commands. This ensured that the War Party, under the leadership of Lord Fairfax, took control of the parliamentary army; this meant that the army leaders shared the same aims. The Self-Denying Ordinance also gave birth to the New Model Army, which destroyed the King’s cavalry at the Battle of Naseby. This suggests that Self-Denying Ordinance was at the centre of Parliament’s triumph during the First Civil War.
In conclusion, the Self-Denying Ordinance was the most advantage held by Parliament during the First Civil War. This ordinance allowed for the creation of the New Model Army and ensured that the Parliamentary army leaders shared the same aims. Meanwhile, Charles failed to stop the rivalry between his soldiers and therefore was unable to install a national war strategy.