Notable Greek seafarers include people such as Pytheas of Marseilles, Scylax of Caryanda who sailed to Iberia and beyond, Nearchus, the 6th century merchant and later monk Cosmas Indicopleustes (Cosmas who sailed to India) and the explorer of the Northwestern passage Juan de Fuca. In later times, the Romioi plied the sea-lanes of the Mediterranean and controlled trade until an embargo imposed by the Roman Emperor on trade with the Caliphate opened the door for the later Italian pre-eminence in trade.