A raid on Cádiz, led by privateer Francis Drake in April 1587, had captured or destroyed about 30 ships and great quantities of supplies, setting preparations back by a year. There is also evidence that a letter from Elizabeth's security chief and spymaster, Sir Francis Walsingham, to her ambassador in Istanbul, William Harborne, sought to initiate Ottoman Empire fleet manoeuvres to harass the Spaniards, but there is no evidence for the success of that plan. Philip initially favoured a triple attack, starting with a diversionary raid on Scotland, while the main Armada would capture either the Isle of Wight or Southampton to establish a safe anchorage in The Solent. The Duke of Parma would then follow with a large army from the Low Countries crossing the English Channel. Parma was uneasy about mounting such an invasion without any possibility of surprise. The appointed commander of the Armada was the highly experienced Álvaro de Bazán, Marquis of Santa Cruz, but he died in February 1588, and the Duke of Medina Sidonia, a high-born courtier, took his place. While a competent soldier and distinguished administrator, Medina Sidonia had no naval experience. He wrote to Philip expressing grave doubts about the planned campaign, but his message was prevented from reaching the King by courtiers on the grounds that God would ensure the Armada's success.