 The road project formed part of Abd al-Malik's centralization drive, special attention being paid to Palestine due to its critical position as a transit zone between Syria and Egypt and Jerusalem's religious centrality to the caliph.A major component of Abd al-Malik's centralization and Islamization measures was the institution of an Islamic currency.The Byzantine gold "solidus" was discontinued in Syria and Egypt, the likely impetus being the Byzantines' addition of an image of Christ on their coins in 691/92, which violated Muslim prohibitions on images of prophets.