Neo-Sumerian in the context of "Ziggurat of Ur"

King of Sumer and Akkad (Sumerian: 𒈗𒆠𒂗𒄀𒆠𒌵 lugal-ki-en-gi-ki-uri, Akkadian: šar māt Šumeri u Akkadi) was a royal title in Ancient Mesopotamia combining the titles of "King of Akkad", the ruling title held by the monarchs of the Akkadian Empire (2334–2154 BC) with the title of "King of Sumer". The title simultaneously laid a claim on the legacy and glory of the ancient empire that had been founded by Sargon of Akkad (r. 2334–2279 BC) and expressed a claim to rule the entirety of lower Mesopotamia (composed of the regions of Sumer in the south and Akkad in the north). Despite both of the titles "King of Sumer" and "King of Akkad" having been used by the Akkadian kings, the title was not introduced in its combined form until the reign of the Neo-Sumerian king Ur-Nammu (c. 2112–2095 BC), who created it in an effort to unify the southern and northern parts of lower Mesopotamia under his rule. The older Akkadian kings themselves might have been against linking Sumer and Akkad in such a way.

In later centuries of Mesopotamian history, when the major kingdoms were Assyria and Babylon, the title was mostly used by monarchs of Babylon since they ruled lower Mesopotamia. For Assyrian kings, the title became a formal assertion of authority over the city of Babylon and its surroundings; only those Assyrian rulers who actually controlled Babylon used the title and when Assyria permanently lost control of Babylon to the Neo-Babylonian Empire, the rulers of that empire began using it instead. The final king to claim to be the King of Sumer and Akkad was Cyrus the Great (r. c. 559–530 BC) of the Achaemenid Empire, who assumed several traditional Mesopotamian titles after his conquest of Babylon in 539 BC.

King of the Four Corners of the World (Sumerian: lugal-an-ub-da-limmu-ba, Akkadian: šarru kibrat arbaim, šar kibrāti arbaʾi, or šar kibrāt erbetti), alternatively translated as King of the Four Quarters of the World, King of the Heaven's Four Corners or King of the Four Corners of the Universe and often shortened to simply King of the Four Corners, was a title of great prestige claimed by powerful monarchs in ancient Mesopotamia. Though the term "four corners of the world" does refer to specific geographical places within and near Mesopotamia itself, these places were (at the time the title was first used) thought to represent locations near the actual edges of the world and as such, the title should be interpreted as something equivalent to "King of all the known world", a claim to universal rule over the entire world and everything within it.

The title was first used by Naram-Sin of the Akkadian Empire in the 23rd century BC and was later used by the rulers of the Neo-Sumerian Empire, after which it fell into disuse. It was revived as a title by a number of Assyrian rulers, becoming especially prominent during the Neo-Assyrian Empire. The final ruler to claim the title was the first Persian Achaemenid king, Cyrus the Great, after his conquest of Babylon in 539 BC.

The Ziggurat (or Great Ziggurat) of Ur (Sumerian: 𒂍𒋼𒅎𒅍 é-temen-ní-gùru "Etemenniguru", meaning "house whose foundation creates terror") is a Neo-Sumerian ziggurat in what was the city of Ur near Nasiriyah, in present-day Dhi Qar Province, Iraq. The structure was built during the Early Bronze Age (21st century BC) by King Ur-Nammu of the Third Dynasty of Ur. It had crumbled to ruins by the 6th century BC of the Neo-Babylonian period, when it was restored by King Nabonidus.

Its remains were excavated in the 1920s and 1930s by international teams led by Sir Leonard Woolley. Under Saddam Hussein in the 1980s, they were encased by a partial reconstruction of the façade and the monumental staircase. Today, Ur Tourist City is being developed adjacent to the site to serve visiting pilgrims and tourists. The Ziggurat of Ur is the best-preserved of those known from Mesopotamia, besides the ziggurat of Dur Untash (Chogha Zanbil). It is one of three well-preserved structures of the Neo-Sumerian city of Ur, along with the Royal Mausolea and the Palace of Ur-Nammu (the E-hursag).