partially overlaps with the Hassuna and early Ubaid. Ubaid culture (c. 6500–3800 BC, Southern Mesopotamia) The Ubaid period (c. 6500–3800 BC) is a prehistoric period of Mesopotamia. The name derives from Tell al-'Ubaid in Southern Mesopotamia, where the earliest large excavation of Ubaid period material was conducted initially by Henry Hall and later by Leonard Woolley. In South Mesopotamia the period is the earliest known period on the alluvial plain although it is likely earlier periods exist obscured under the alluvium. In the south it has a very long duration between about 6500 and 3800 BC when it is replaced by the Uruk period. In North Mesopotamia, Ubaid culture expanded during the period between about 5300 and 4300 BC. It is preceded by the Halaf period and the Halaf-Ubaid Transitional period and succeeded by the Late Chalcolithic period. The new period is named Northern Ubaid to distinguish it from the proper Ubaid in southern Mesopotamia. With Ubaid 3 (circa 4500 BC) numerous examples of Ubaid pottery have been found along the Persian Gulf, as far as Dilmun, where Indus Valley civilization pottery has also been found. Stamps seals start to depict animals in stylistic fashion, and also bear the first known depiction of the Master of Animals at the end of the period, circa 4000 BC. Historic Mesopotamia Sumerian period (c. 4000–2270 BC) The rise of the non-Semitic-speaking Sumerian culture spans a period of about two millennia, and saw the development of sophisticated artistic traditions, as well as the invention of writing, first through pictographic signs, and then through cuneiforms. Pre-Dynastic period: Uruk (c. 4000 to 3100 BC) The Protoliterate or Uruk period, named after the city of Uruk in southern Mesopotamia, (ca. 4000 to 3100 BC) existed from the protohistoric Chalcolithic to Early Bronze Age period, following the Ubaid period and succeeded by the Jemdet Nasr period generally dated to 3100–2900 BC. It saw the emergence of urban life in Mesopotamia, and the beginnings of Sumerian civilization, and also the first "great creative age" of Mesopotamian art. Slightly earlier, the northern city of Tell Brak, today in Syria, also saw urbanization, and the development of a temple with regional significance. This is called the Eye Temple after the many "eye idols", in fact votive offerings, found there, a type distinctive to this site. The stone Tell Brak Head, 7 inches high, shows a simplified face; similar heads are in