The earliest phase includes the founding of the city, sometime after 4000 B.C., in a transitional era between the neolithic age and the bronze age. The first society to live at Ur did not do so for long, as it was destroyed in a flood which wiped out all settlements in the Ancient Near East. The city was rebuilt by settlers who had a better knowledge of copper, and by a later group - "protoliterate" - which was early in the process of learning to write.
The second phase of Ur's history includes its first two dynasties. By 2700 B.C., Ur had become powerful and wealthy. It became the center of an expanded area, the Sumerian kingdom, which it ruled. It grew to include the whole Mesopotamian Valley. When a Sumerian king died, he was buried with his government officials, servants, and a group of women. By 2700 B.C., this practice was already an old tradition. Inscriptions from this era record that Sargon of Akkad, a ruler from a region north of Ur, was expanding and occupying the region around Ur. Traders from Ur at this time had contact with merchants as far away as India. The magical and superstitious practices of this phase - perhaps not quite yet religions - included human sacrifices, atop ziggurats, intended to persuade idols to grant good weather, good harvests, and military successes.
Sometime after 2200 B.C., Ur had freed itself from Akkad's influence and was once again an independent kingdom ruling the surrounding region. This was the third dynasty. A large and impressive ziggurat was built during this third phase, manifesting complex engineering. It shows that the citizens of Ur had developed advanced principles of architecture, including columns, arches, domes, and vaults, and the sophisticated mathematics needed to design them. The structure demonstrated the principle of entasis, in which an optical illusion is produced: a curved line appears straight, and a straight line appears curved. Some of these architectural and mathematical innovations occurred as early as the first two dynasties.
A fourth phase of Ur's history saw the city lose its political importance, no longer the seat of a major monarch. Its significance in terms of import and export remained for a while, but then it fell into disrepair and neglect.
A fifth phase saw the city's financial and cultural status revived, as it became part of the Neo-Babylonian empire. Between 605 B.C. and 562 B.C., king Nebuchadnezzar II substantially rebuilt the city. Politically, however, Ur was ruled from Babylon as part of the empire, and shared its sudden rise, relatively brief era of supremacy, and quick demise when the Persians overtook the empire.
During the sixth phase, Ur was part of Cyrus's empire, given freedom to carry on its local religion and culture as long as it paid taxes and gave military support to the Persians. The city, however, began to decay, as the Euphrates River gradually changed its course, making agriculture impossible. Sometime after 317 B.C., Ur was abandoned, and the desert sands gradually covered its remains for archeologists to find 2000 years later.
The city is deserted now, visited by archeologists and the most adventurous tourists. Two miles away is a small railroad station, named 'Ur Junction', keeping the ancient name of the great city alive in modern times.
Ur is mentioned often in certain history courses. The city has played significant roles in various scenarios over the ages. But in any discussion of an event relating to Ur, it must first be established, during which phase of Ur's history that event took place. These phases are meaningfully different from one another, and provide the backdrop for such narratives.
