In her book, The Mystery of the Cross: Bringing Ancient Christian Images to Life, Judith Couchman quotes William Wood Seymour from his book The Cross in Tradition, History and Art:

According to tradition, (during the crucifixion) our Lord’s back was turned toward Jerusalem, which was in the east and his face toward the west.  This may have been a refinement of cruelty on the part of the executioners.  Jesus’  back was placed toward the capital nation of whom the Roman governor had written he was “King,” and his face turned to the setting sun, not only to remind him of his departing glory, as his enemies  folly deemed, but that no torture, however, petty, yet agonizing, as the blaze of the sun would be, might be spared.

May the cross of Christ never fade in its importance or our memories.