sand storms in antiquity. In the modern western countries, the European "Age of Sail" is the period in which international trade and naval warfare were both dominated by sailing ships. The age of sail mostly coincided with the age of discovery, from the 15th to the 18th century. After the 17th century, English naval maps stopped using the term of British Sea for the English Channel. From 15th to the 18th centuries, the period saw square rigged sailing ships carry European settlers to many parts of the world in one of the most important human migrations in recorded history. This period was marked by extensive exploration and colonization efforts on the part of European kingdoms. The sextant, developed in the 18th century, made more accurate charting of nautical position possible. Notable individuals Juan of Austria was a military leader whose most famous victory was in the naval Battle of Lepanto in 1571. Philip had appointed Juan to command the naval forces of the Holy League which was pitted against the Ottoman Empire. Juan, by dint of leadership ability and charisma, was able to unite this disparate coalition and inflict a historic defeat upon the Ottomans and their corsair allies in the Battle of Lepanto. His role in the battle is commemorated in the poem "Lepanto" by G. K. Chesterton. Maarten Tromp was an officer and later admiral in the Dutch navy. In 1639, during the Dutch struggle for independence from Spain, Tromp defeated a large Spanish fleet bound for Flanders at the Battle of the Downs, marking the end of Spanish naval power. In a preliminary battle, the action of 18 September 1639, Tromp was the first fleet commander known to deliberately use line of battle tactics. His flagship in this period was Aemilia. In the First Anglo-Dutch War of 1652–1653 Tromp commanded the Dutch fleet in the battles of Dungeness, Portland, the Gabbard and Scheveningen. In the last of these, he was killed by a sharpshooter in the rigging of William Penn's ship. His acting flag captain, Egbert Bartholomeusz Kortenaer, on kept up fleet morale by not lowering Tromp's standard, pretending Tromp was still alive. Cornelis Tromp was a Commander in Chief of the Dutch and Danish navy. In 1656 he participated in the relief of Gdańsk (Danzig). In 1658 it was discovered he had used his ships to trade in luxury goods; as a result he was fined