to modern diplomatic representatives were fulfilled by a proxenos, a citizen of the host city who had friendly relations with another city, often through familial ties. In times of peace, diplomacy was even conducted with non-Hellenistic rivals such as the Achaemenid Empire of Persia, through it was ultimately conquered by Alexander the Great of Macedon. Alexander was also adept at diplomacy, realizing that the conquest of foreign cultures would be better achieved by having his Macedonian and Greek subjects intermingle and intermarry with native populations. For instance, Alexander took as his wife a Sogdian woman of Bactria, Roxana, after the siege of the Sogdian Rock, in order to placate the rebelling populace. Diplomacy remained a necessary tool of statecraft for the great Hellenistic states that succeeded Alexander's empire, such as the Ptolemaic Kingdom and Seleucid Empire, which fought several wars in the Near East and often negotiated peace treaties through marriage alliances. Ottoman Empire Relations with the Ottoman Empire were particularly important to Italian states, to which the Ottoman government was known as the Sublime Porte. The maritime republics of Genoa and Venice depended less and less upon their nautical capabilities, and more and more upon the perpetuation of good relations with the Ottomans. Interactions between various merchants, diplomats and clergymen hailing from the Italian and Ottoman empires helped inaugurate and create new forms of diplomacy and statecraft. Eventually the primary purpose of a diplomat, which was originally a negotiator, evolved into a persona that represented an autonomous state in all aspects of political affairs. It became evident that all other sovereigns felt the need to accommodate themselves diplomatically, due to the emergence of the powerful political environment of the Ottoman Empire. One could come to the conclusion that the atmosphere of diplomacy within the early modern period revolved around a foundation of conformity to Ottoman culture. East Asia One of the earliest realists in international relations theory was the 6th-century BC military strategist Sun Tzu (d. 496 BC), author of The Art of War. He lived during a time in which rival states were starting to pay less attention to traditional respects of tutelage to the Zhou dynasty (c. 1050–256 BC) figurehead monarchs while each vied for power and total conquest. However, a great deal of diplomacy in establishing allies, bartering land, and signing peace treaties was necessary for each warring state, and the idealized role of the "persuader/diplomat"