[5] Although Lieutenant-Admiral Maarten Tromp had formed a line against the Spanish fleet in 1639 in the action of 18 September 1639, this was not a planned formation but a desperate attempt to hold off a greatly superior, but badly organised, enemy.

[13] The Second Anglo-Dutch War arose from an escalation of existing commercial tensions between England and the Netherlands in 1664, involving English provocations in North America and West Africa.

[16] The existence of this treaty strengthened the Dutch resolve not to make significant concessions, as Johan de Witt believed it would prevent England declaring war.

[21] De Witt also achieved the completion of many new warships, with twenty-one ordered during the early stages of the war to augment the existing fleet and sixty-four planned in 1664, including several large flotilla flagships comparable in armament to all but the largest English ones.

De Witt quickly saw that men were critical, not materiel: he sought to deal with the insubordination, lack of discipline and apparent cowardice among captains by executing three and exiling and dismissing others.

Despite the loss of ships and at least 5,000 men killed, wounded or captured, the escape of the bulk of the Dutch fleet frustrated the possibility of England ending the war with a single overwhelming victory.

[28] The existence of five admiralty colleges, each with its own policies on ship construction and armaments, each favouring its local commanders and with variable levels of efficiency, and the reluctance of Grand Pensionary Johan de Witt to appoint Orangist officers, all led to difficulty in creating a unified navy.

In view of the significant number of casualties among senior English officers and noble volunteers, including three killed next to the Duke, Charles insisted that his brother should no longer command at sea.

The delegates recorded that Albemarle would not object to detaching a squadron under Prince Rupert to block the Strait of Dover, provided he were left with at least 70 ships to fight the Dutch.

[38] Rupert's initial instructions were to attack Beaufort's fleet, whose original 32 ships included several weakly armed, poorly manned or slow vessels.

[42] Much of the problem was that Charles II and his ministers had planned for a short war, but keeping a large fleet in being for a year after the partial victory of Lowestoft put demands on English public finances in 1666 that were almost impossible for it to meet.

[43] Albemarle became increasingly concerned about the small numbers of ships under his command at the mouth of the Thames as May progressed, particularly after he received intelligence that the Dutch fleet was preparing to leave its harbours.

De Ruyter's careful planning, keeping the centre and rear of the English fleet occupied while he rescued Tromp was in contrast to Berkeley's impetuosity of the previous day.

Ayscue was criticised for not pressing the disordered Dutch more closely,[78] although his ships were also vulnerable to van Nes who had begun to turn north and could have joined de Ruyter quite quickly if the latter were attacked.

The list of ships leaving the Dutch fleet was growing: the Hollandia had been sent home together with the Gelderland, Delft, Reiger Asperen and Beschermer in order to guard the three captured English vessels.

He was later accused of attempting to pass the responsibility for any defeat in the uncertain contest to van Nes, but there was no established rule at that time about when admirals should change ships: Albemarle had remained on the Royal Charles the previous day when it anchored to refit during the fighting without his conduct being questioned.

As it held a leeward position, its guns had greater range which, with its superior numbers, made it clear by the early afternoon that the day's outcome could be decided by attrition.

At the time, Albemarle believed that these were part of a fresh force, the English intelligence network in Holland having reported that the Dutch would retain a fourth squadron as a tactical reserve.

However, the crew panicked and a certain Lambeth struck the flag, forcing Ayscue to surrender to Tromp on the Gouda, the only time in history an English admiral of so high a rank was captured at sea.

The Victory, now commanded by its lieutenant, John Narborough, and its three consorts were attacked by Tromp and van Nes with around 25 ships but managed to manoeuvre to avoid capture and all survived the battle.

[117] De Ruyter's patience was based on the probability that some or all of van Nes and Tromp's 25 ships would return to the main action, which they began to do on the lee side of the English fleet from around 3pm.

At first, Albemarle thought that de Ruyter intended to link up with van Nes and escape with as many Dutch ships as possible, and his exhausted forces with little ammunition left did not move to oppose this manoeuvre.

[121] De Ruyter's unexpected attack, when Albemarle appeared to be on the point of destroying Tromp's squadron, caused some British captains to lose their nerve, and things began to go badly for the English fleet.

[122] Almost immediately, the Royal James lost its main topmast, its mizzen mast and several major yards: it was now disabled and the rest of the squadron, rather than continuing against the Dutch, withdrew to defend their flagship and tow it westward.

[124] Those English ships of Teddiman's squadron and others in the rear that stayed in line were able to follow Albemarle westwards, as the Dutch were as short of gunpowder as their opponents, and aimed to board and capture them.

Albemarle and Rupert later claimed that their initial aim of their withdrawal was to unite and, if necessary renew the fight the next day, but the poor condition of many ships and their lack of ammunition decided them to continue homeward.

[127] De Ruyter later claimed that he had called off the pursuit of the English fleet because of a thick fog which made navigation difficult, otherwise he would have followed the ships as far as their home ports.

The deeply religious De Ruyter interpreted the sudden unseasonal fog bank as a sign from God, writing in his logbook "that He merely wanted the enemy humbled for his pride but preserved from utter destruction".

However, the fog was only temporary and de Ruyter had only around 40 ships under his immediate command, with others disabled and returning to the Netherlands or dealing with prizes, and Albemarle had almost as many, including several large vessels, which posed a significant risk to the exhausted Dutch fleet.

[142] England had gone to war in the expectation of an early victory that would not overstretch its government's fragile financial position, but both it and the Netherlands had put such unprecedented efforts into providing ships and men that no decisive naval victory was possible, and severe English financial difficulties and the Dutch need to resume unrestricted commercial activity created the conditions for peace without resolving all the underlying causes for the conflict [143] The Four Days' Battle is dramatized in the Dutch film Michiel de Ruyter (2015), although it is not clear which phase of the battle is shown.