Al-Azd was the first tribe to inhabit Arabia, particularly the Northwestern part of the Arabian peninsula. Following the fall of their Nabatean Kingdom, they invaded the lands of modern-day Yemen from the Himyarites (modern-day Yemeni people).They built a dam and settled there until the lands were irrigated by the Ma'rib Dam, which is thought by some to have been one of the engineering wonders of the ancient world because of its size. When the dam collapsed for the third time in the 1st century CE, much of the Azd tribe left Marib and dispersed. The tribe descended through Ishmael.