The military weakness of the Protestants is illustrated by the fact that they only had a limited army of 2,000 mercenaries under the leadership of Ernst von Mansfeld. Mansfeld had little success and was defeated in both 1620 by the Catholic League and 1626 by Wallenstein’s army at Dessau Bridge. This weak defence made the Protestants relatively easy to defeat compared to the strength of the Catholic military which consisted of a joint effort between the Catholic League, Imperial troops and the Spanish Habsburgs. In comparison, the Protestants lacked unity and were not working as a unit because they had to fight and protect different territories. This gave them a disadvantage against the Catholic forces. A lack of support is mainly to blame for the weakness of the Protestants military force. For example, Frederick would have expected the support of the English since King James I was Frederick’s father-in-law. However, James I was wary of the strength of the Habsburgs and understood that even with this help, they would be too strong to overcome. Another reason England would not support Frederick was that the King was looking to obtain a marriage alliance between his son and heir to the throne, Charles, and the Habsburgs. Being involved with Frederick would prevent him from doing so successfully. The support the Protestants did have, for example Bethlen Tabor from Transylvania, was weakened and had to retreat due to lack of money. This was a serious loss to the Protestants as he had already proved he had the ability to defeat the Habsburgs. The Danish also lacked allies in their phase of the war between 1625-29 which allowed the Catholic to focus their attention on one opponent. Their military ineffectiveness is proven in 1626 when the Danes we defeated at the Battle of Lutter-am-Baremberg by Tilly’s men. Defeats such as these are evidence to the fact that Protestant resistance was severely limited, making them an easy feat for the Habsburgs.
However, a large factor contributing to Habsburg success is their own strengths rather than their opponent’s weaknesses. The Habsburgs showed strengths both politically and militarily in comparison to their weaker rivals. Their political strengths were important in helping them defeat the Protestants because they needed support in order to form a successful attack strategy. An example of the Habsburgs political strength is in 1620, when Spain committed itself heavily to the Empire in the Treaty of Munich. The Treaty was significant as the Spanish were powerful and had an experienced army that soon took control of the Palatinate, which would have been difficult to achieve without their help. Moreover, in the Bohemian phase of the war the Habsburgs received subsidies from the Pope which was significant because it allowed them to strengthen their position, therefore linking to military strengths. The Catholic League also provided support diplomatically despite the fact it was led by Maximilian, Duke of Bavaria who was a rival of the Habsburgs. This is a strong statement illustrating the unity of the Catholics and the Habsburgs because they were able to postpone political rivalries between themselves in order to create an alliance against the Protestants which would be difficult to break. This is significant because, as mentioned previously, the Protestants did not have such alliances and it was a characteristic of the Habsburgs that gave them the upper hand.
The Catholics also excelled in their military strength in comparison to their Protestant opponents. Their military strength is illustrated by the fact they could use their own troops and Ferdinand took advantage of this by sending in 7000 of his own men. On top of this, the Spanish Netherlands raised 20,000 men under the leadership of Spinola to help the Habsburg cause which is significant as it provided physical manpower to the Habsburgs army instead of just funding them. Maximilian reactivated the Catholic League alliance and sent in troops under the command of Tilly showing the Catholic League were a source of not only diplomatic support but militarily as well. The Catholic League’s military involvement was significant because Tilly succeeded in defeating Mansfeld in 1620, showing they provided the Habsburgs with support that was active in defeating the Protestants. The military strength of the Habsburgs is also due to their method of attack; whilst Spinola attacked the Palatinate, Tilly and the Catholic League defeated Mansfeld at the Battle of White Mountain in 1620. They were successful in working together whereas their Protestant opponents did not share such unison. This gave them the advantage of being able to defeat the Protestants easier as they were capable of forming a stronger attack that their opponents could not defend themselves from.