During the Medieval period, trade underwent further changes. Localised trading based on transactional exchange and bartering systems was slowly transformed as transportation improved and new geographic markets were opened. From the 11th century, the Crusades helped to open up new trade routes in the Near East, while the adventurer and merchant, Marco Polo stimulated interest in the far East in the 12th and 13th centuries. Medieval merchants began to trade in exotic goods imported from distant shores including spices, wine, food, furs, fine cloth, notably silk, glass, jewellery and many other luxury goods. As trade between countries or regions grew, trade networks became more complex and different types of sellers filled in the spaces within the network. During the thirteenth century, European businesses became more permanent and were able to maintain sedentary merchants in a home office and a system of agents who operated in different geographic markets. Exchange was often conducted at arm's length, rather than face-to-face.