Soon after the death of the Yongle Emperor the expansion policy of the Ming was replaced with that of retrenchment in southern Manchuria (Liaodong). Around 1442, a defence wall was constructed to defend the northwestern frontier of Liaodong from a possible threat from the Jurched-Mongol Oriyanghan. In 1467–68 the wall was expanded to protect the region from the northeast as well, against attacks from Jianzhou Jurchens. Although similar in purpose to the Great Wall of China, this "Liaodong Wall" was of a simpler design. While stones and tiles were used in some parts, most of the wall was in fact simply an earthen dike with moats on both sides.