Prince Rupert at Lisbon, 1649-50
On 20 October 1649, Prince Rupert set sail from Kinsale harbour in his flagship the Constant Reformation (40 guns), with Prince Maurice's flagship the Convertine (40), the Swallow (36) and the Blackamoor Lady (18), which had all been in the squadron that sailed from Helvoetsluys in January. Three additional ships, the Scott (30 guns), the Mary (14), and the Black Knight (14), were converted prizes. The Royalist squadron sailed south from Ireland, across the Bay of Biscay towards Portugal. Earlier in the year, Rupert had received a favourable response when he wrote to King John IV requesting permission to base his ships at Lisbon if he should be forced to leave Ireland.
After an eventful voyage during which five prizes were taken, the Royalists arrived off Lisbon around 20 November 1649. Three of the prizes were sold and two were taken into the squadron as the Second Charles (40 guns) and the Henry (36). Rupert also bought a Dutch ship, which became the Black Prince (30). The Blackamoor Lady was sold and the Convertine laid up in order to finance guns and crews for the new ships.
Although King John was sympathetic to Rupert, his chief minister the Count de Miro feared that open support for the English Royalists might have a detrimental effect on Portuguese trade and also encourage the Commonwealth into an alliance with Portugal's enemy Spain. De Miro was supported by the Portuguese mercantile community. Objections were raised to the sale of a Portuguese cargo from one of the captured ships and Prince Maurice was prevented from embarking on a voyage to take further prizes. However, Rupert and Maurice worked to strengthen their position at Lisbon by making frequent visits to King John and joining in the social life of the Portuguese court. They became friendly with the local nobility and even gained the support of the clergy, who said that to abandon the princes to the English rebels would bring dishonour to Portugal.
Early in 1650, the Council of State denounced Rupert as a pirate and commissioned General-at-Sea Robert Blake to destroy the Royalist squadron. Blake sailed from Portsmouth in March 1650 with a powerful fleet of fifteen ships. His flagship was the George (54 guns), his vice-admiral was Robert Moulton in the Leopard (56), his rear-admiral was Richard Badiley in the Entrance (46). Other warships were the Bonaventure (42), the Adventure (40), the John (30), the Assurance (32), the Constant Warwick (32), the Tiger (36), the Providence (30) and the Expedition (30). The fleet was supplemented by the fireship Signet and the ketches Tenth Whelp, William and Patrick. Charles Vane, brother of Sir Henry Vane, accompanied the expedition with responsibility for conducting diplomatic negotiations with the Portuguese government, which at the time did not recognise the Commonwealth of England.
Blake's fleet arrived at Cascaes Bay at the mouth of the River Tagus on 10 March 1650. Blake immediately sent a message to King John demanding the use of Lisbon harbour for the Commonwealth fleet and Portugal's co-operation against Prince Rupert's pirates. The following day, however, Portuguese forts fired warning shots when Blake attempted to sail up the River Tagus towards Rupert's anchorage. Blake agreed to withdraw pending diplomatic negotiations. Charles Vane negotiated a concession from the Portuguese whereby the Commonwealth fleet could enter Oeiras Bay in the event of bad weather. Blake immediately took advantage of this to anchor two miles downriver from Rupert's ships.
As the negotiations proceeded during the following weeks, the Portuguese agreed to allow the Commonwealth sailors the freedom of the harbour, which resulted in several tavern brawls between crews of the rival fleets. Following an alleged ambush and assassination attempt by Commonwealth sailors when Rupert and Maurice were on a hunting trip, the Royalists retaliated by sending a boat disguised as a fruit seller booby-trapped with a firebomb, which almost succeeded in blowing up the Leopard. In another encounter, Rupert's men attacked a watering party from the Bonaventure. One sailor was killed and three taken prisoner. Despite these clashes, however, the situation remained deadlocked. King John refused to allow Blake to attack Rupert's ships while they were under Portuguese protection, and Rupert could not risk leaving Lisbon harbour with the powerful Commonwealth fleet nearby.
In mid-May, Blake withdrew from the River Tagus, hoping to lure out the Royalist squadron. Around 21 May, Blake seized ten English merchant ships chartered to an outbound Portuguese fleet sailing for Brazil. When Blake offered to release the ships if King John handed over Prince Rupert's ships, the furious King ordered the arrest of all English subjects in Lisbon known to be sympathetic to the Commonwealth and forbade Blake from entering the Tagus or collecting water from the mainland. A few days later, General-at-Sea Edward Popham reinforced Blake's fleet with a further eight ships: the 68-gun Resolution, the Andrew (42), the Phoenix (36), the Satisfaction (26), four armed merchantmen and a much-needed store ship. Popham carried revised orders from the Council of State which authorised Blake to attack Portuguese merchant shipping if King John continued to obstruct the Commonwealth.
Under increasing pressure from the English Commonwealth and from his own advisers, King John tried to find an honourable resolution to the situation by offering the use of a Portuguese fleet to shield Prince Rupert's escape from Lisbon. On 26 July, when eight of Blake's ships had gone to Cadiz to replenish supplies, Rupert's squadron sailed out of Lisbon harbour supported by two French ships, thirteen Portuguese warships and a number of fireships and smaller craft. The allies were reluctant to engage the Commonwealth fleet and although Blake was determined to contain Rupert's squadron, he did not want to risk a full engagement until the Cadiz squadron had returned. For three days, the opposing fleets manoeuvred at the mouth of the Tagus with occasional exchanges of gunfire as Rupert tried to take advantage of the shifts in the wind and tide to evade Blake's ships and escape to the open sea. By the morning of 29 July, the Cadiz squadron had returned to bring the Commonwealth fleet back to full strength. As Blake prepared to launch a full-scale attack, the allied fleet withdrew to the shelter of the guns of Lisbon harbour.
Early in September 1650, the Council of State recalled Popham with as many ships as could be spared from the Commonwealth fleet. The blockade of Lisbon was expensive to maintain and ships were also needed to support Cromwell's invasion of Scotland. On 3 September, Popham sailed for England with eight ships, including the powerful Resolution, leaving Blake with nine ships to watch Prince Rupert. Three days after Popham's departure, the Royalists took advantage of foggy conditions to make another attempt to escape but were sighted and engaged by the Commonwealth fleet. During this encounter, Rupert's flagship the Constant Reformation was attacked by Blake's flagship the George supported by the Phoenix and Expedition. A broadside from the George brought down Constant Reformation's fore-topmast, and the Royalists were once again forced to withdraw to Lisbon.
On 14 September, Blake sighted the homeward-bound Portuguese Brazil fleet making for Lisbon. With authority from the Council of State to attack Portuguese trade, Blake moved in to intercept the fleet. After a three-hour battle, Blake in the George captured the Portuguese vice-admiral's ship while his brother Benjamin Blake commanding the Assurance captured the rear admiral. The Portuguese flagship escaped with the loss of her mainmast. Only nine of the twenty-three ships in the fleet reached Lisbon; one was sunk and the rest captured. The loss of the Brazil fleet, with its rich cargo that included 4,000 chests of sugar, was a serious blow to the Portuguese economy and finally persuaded King John to insist that Prince Rupert's squadron should leave Lisbon.
Towards the end of September, Blake's fleet was obliged to sail to Cadiz to replenish supplies and to arrange for the disposal of the Portuguese prizes. With Blake gone, Rupert took the opportunity to escape. On 12 October, he sailed with six ships from the River Tagus and made for the Mediterranean.
John Barratt, Cromwell's Wars at Sea (Barnsley 2006)
S.R. Gardiner, History of the Commonwealth and Protectorate vol. i (London 1903)
Frank Kitson, Prince Rupert, admiral and general-at-sea (London 1998)
Eliot Warburton, Memoirs of Prince Rupert and the Cavaliers vol iii (London 1849)
Royalist vessels of the English Civil Wars and Commonwealth 3decks naval warfare wiki