occur: high technological development, the development of important urban agglomerations with imposing monumental structures (the most characteristic of these is Level IV of Eanna), the appearance of state institutions, and the expansion of the Uruk civilization throughout the whole Near East. Jemdet Nasr period This phase of "Late Uruk" is followed by another phase (level III of Eanna) in which the Uruk civilization declined and a number of distinct local cultures developed throughout the Near East. This is generally known as the Jemdet Nasr period, after the archaeological site of that name. Its exact nature is highly debated, and it is difficult to clearly distinguish its traits from those of the Uruk culture, so some scholars refer to it as the "Final Uruk" period instead. It lasted from around 3000 to 2900 BC. Alternative chronology In 2001, a new chronology was proposed by the members of a colloquium at Santa Fe, based on recent excavations, especially at sites outside Mesopotamia. They consider the Uruk period to be the "Late Chalcolithic" (LC). Their LC 1 corresponds to the end of the Ubaid period and ends around 4200 BC, with the beginning of LC 2, which is the first phase of the Uruk period. They divide "Old Uruk" into two phases, with the dividing line placed around 4000 BC. Around 3800 BC, LC 3 begins, which corresponds to the "Middle Uruk" phase and continues until around 3400 BC, when it is succeeded by LC 4. It rapidly transitions to LC 5 (Late Uruk), which continues until 3000 BC. Some other chronological proposals have also been put forward, such as by the ARCANE team (Associated Regional Chronologies for the Ancient Near East). Although the chronology of the Uruk period is full of uncertainties, it is generally agreed to have a rough span of a thousand years covering the period from 4000 to 3000 BC and to be divided into several phases: an initial urbanisation and elaboration of Urukian cultural traits marks the transition from the end of the Ubaid period (Old Uruk), then a period of expansion (Middle Uruk), with a peak during which the characteristic traits of the 'Uruk civilization' are definitively established (Late Uruk), and then a retreat of Urukian influence and increase in cultural diversity in the Near East along with a decline of the 'centre'. Some researchers have attempted to explain this final stage as the arrival of new