São Martinho (in Spanish: San Martin, meaning Saint Martin), built as a Portuguese Navy galleon, became the flagship of Duke of Medina Sedonia, commander-in-chief of the Spanish Armada.
When Portugal came under the rule of King Philip II of Spain, in 1580, the Portuguese had just finished building a large galleon named São Martinho. She was known by Castilians as San Martín. At the time of forming the Spanish Armada, the São Martinho was found to be the best of the fleet and was chosen as the flagship of the Armada commander-in-chief, Duke of Medina Sidonia.
São Martinho had an overall length of about 180 feet with a beam of about 40 feet. She carried 48 heavy guns on two enclosed gun decks, plus multiple smaller weapons. According to a painting by Hendrik Cornelisz Vroom, National Maritime Museum, Greenwich, San Martin had three masts, two square-rigged masts and one lateen mizzen-mast. She was shown with a stern gallery and with the long beakhead characteristic of a galleon. The foremast was set forward of the forecastle.
São Martinho suffered heavy damage in the battle of Gravelines in July 1588 when a group of English ships led by Sir Francis Drake in the Revenge bore down upon her. With the assistance of another galleon she escaped the attack and led the Armada back to Spain through a ferocious storm, where she had to be towed into port at Santander. Because of a storm, the San Martin had to take refuge at Laredo, where Medina Sidonia found the galleass Napolitana and other ships in harbor. The ship was full of sick crew and was itself in sad condition.[1]