The greater ancient Near East (including Egypt) offers some of the oldest evidence of the existence of international relations, since it was there that states first developed (the city-states and empires of Mesopotamia, the Levant, and Egypt) around the 4th millennium B.C.E. Almost 3000 years of the evolution of diplomatic relations are thus visible in sources from the ancient Near East. However, because only certain periods are well documented within that timespan, there remain many gaps in the modern study of diplomacy in this era.