Memphis declined after the Eighteenth Dynasty with the rise of Thebes and the New Kingdom, but was revived under the Persians, before falling firmly into second place following the founding of Alexandria. Under the Roman Empire, Alexandria remained the most important Egyptian city. Memphis remained the second city of Egypt until the establishment of Fustat (or Fostat) in 641 AD. Afterward it was largely abandoned and became a source of stone for the surrounding settlements. It was still an imposing set of ruins in the twelfth century, but soon became little more than an expanse of low ruins and scattered stone.