Anglo-French War (1627–29)

The Anglo-French War of 1627-1629 was part of the Thirty Years' War. It mainly involved actions at sea. The centre of the conflict surrounded the Siege of La Rochelle, in which the English crown supported the French Huguenots in their fight against the French royal forces of Louis XIII of France in 1627-1628. La Rochelle had become the stronghold of the French Huguenots, under its own governance. It was the centre of Huguenot seapower, and the strongest centre of resistance against the central government.

Background
The conflict followed the failure of the Anglo-French alliance of 1624, in which England had tried to find an ally in France against the power of the Habsburg. French politics evolved otherwise however as Cardinal Richelieu came to power in 1624. In 1625, Richelieu used English warships to vanquish the Huguenots at the Recovery of Ré island (1625), triggering outrage in England.

In 1626, France actually concluded a secret peace with Spain, and disputes arose around Henrietta Maria's household. Furthermore, France was building the power of its Navy, leading the English to be convinced that France must be opposed "for reasons of state".

In June 1626, Walter Montagu was sent to France to contact dissident noblemen, and from March 1627 started to organized a French rebellion. The plan was to send an English fleet to encourage rebellion, as a new Huguenot revolt by Henri, Duke of Rohan and his brother Soubise was being triggered.

Ile de Ré expedition
Charles I, who sent his favourite George Villiers, 1st Duke of Buckingham with a fleet of 80 ships. In June 1627 Buckingham organised a landing on the nearby island of Île de Ré with 6,000 men in order to help the Huguenots. Although a Protestant stronghold, Île de Ré had not directly joined the rebellion against the king. On Île de Ré, the English under Buckingham tried to take the fortified city of Saint-Martin-de-Ré in the 1625 Recovery of Ré island, but were repulsed after three months. Small French Royal boats managed to supply St Martin in spite of the English blockade. Buckingham ultimately ran out of money and support, and his army was weakened by diseases. After a last attack on Saint-Martin they were repulsed with heavy casualties, and left with their ships.

La Rochelle expedition
England attempted to send two more fleets to relieve La Rochelle. The first one, led by William Feilding, Earl of Dengbigh, left on April 1628, but returned without a fight to Portsmouth, as Dengbigh "said that he had no commission to hazard the king's ship in a fight and returned shamefully to Portsmouth". A second fleet, organized by Buckingham just before his assassination, was dispatched under the Admiral of the Fleet, the Earl of Lindsey in August 1628, consisting of 29 warships and 31 merchantmen. In September 1628, the English fleet tried to relieve the city. After bombarding French positions and trying to force the sea wall in vain, the English fleet had to withdraw. Following this last disappointment, the city surrendered on October 28, 1628.

Peace
Following these defeats, England would end its involvement with the Thirty Years' War, by negotiating a peace treaty with France in 1629. A peace treaty was also signed with Spain in 1630, also following a failed conflict with the 1625 Cádiz Expedition. England disinvolved itself from European affairs, to the dismay of Protestant forces on the continent.

In England, internal conflict continued between the Monarchy and the Parliament, disputes which would lead to the English Civil Wars of the 1640s. France on the contrary continued to grow more powerful, its Navy becoming even larger as that of England's by 1630.