Despite popular enthusiasm for the Protestant Dutch, and concern at the success of the Catholic Counter-Reformation, English involvement in the Eighty Years' War had been limited to financial support, and provision of volunteer units.

[5] The Thirty Years War began when the Protestant Frederick V of the Palatinate accepted the Crown of Bohemia, replacing Ferdinand II, Catholic heir to the Holy Roman Emperor.

Spinola rapidly gathered his defences and drove off a Dutch relief army led by Maurice of Nassau, Prince of Orange who was attempting to cut off his supply lines.

Sir Edward Cecil, a battle-hardened combat veteran in Dutch service, was appointed commander of the expedition by the Duke of Buckingham, a choice that proved to be ill-considered.

Eventually, Cecil, the commander of the expedition, faced with dwindling supplies, decided there was no alternative but to return to England, having captured few goods and having had no impact on Spain.

[citation needed] Charles I, to protect his own dignity and Buckingham, who had failed to ensure the invasion fleet was well supplied, made no effort to inquire as to the cause of the failure of the expedition.

On 23 August 1628, while organising a second campaign in Portsmouth, Buckingham was stabbed to death at the Greyhound Pub by John Felton, an army officer who had been wounded at the siege of La Rochelle.

A Spanish relief force led by Hendrik van den Bergh failed to get through and as a result the city surrendered to Dutch commander Frederick Henry, Prince of Orange.

[7] In 1629, the important Spanish stronghold of 's-Hertogenbosch was besieged and captured by Frederick Henry's army of 28,000 men which included a number of English and Scottish regiments commanded by Vere.

[8] In 1629, a Spanish naval expedition under Admiral Fadrique de Toledo was sent to liquidate recently established English and French settlements on the Caribbean island of Saint Kitts and Nevis.

Thereafter, expeditions were undertaken by the Duke of Hamilton and Earl of Craven to the Holy Roman Empire in support of the thousands of Scottish and English mercenaries already serving under Gustavus Adolphus of Sweden in that conflict.

[citation needed] With the advent of the War of the Mantuan Succession Spain sought peace with England in 1629 and so arranged a suspension of arms and an exchange of ambassadors.