Neolithic Revolution as irrigation and deforestation which allowed the production of surplus food. Other developments found very widely are the domestication of animals, pottery, polished stone tools, and rectangular houses. These developments, sometimes called the Neolithic package, provided the basis for centralized administrations and political structures, hierarchical ideologies, depersonalized systems of knowledge (e.g. writing), densely populated settlements, specialization and division of labour, more trade, the development of non-portable art and architecture, and property ownership. The earliest known civilization developed in Sumer in southern Mesopotamia (); its emergence also heralded the beginning of the Bronze Age. The relationship of the above-mentioned Neolithic characteristics
Neolithic and Bronze Age rock art in the British Isles the research into rock art has been undertaken by amateurs rather than professional archaeologists, to varying degrees of quality. In 1997, archaeologist Richard Bradley of the University of Reading published "Rock Art and the Prehistory of Atlantic Europe", the first study of such petroglyphs across Atlantic Europe. In 1999, Stan Beckensall published "British Prehistoric Rock Art", the first regional overview of the island's rock art. The purposes of Neolithic and Bronze Age petroglyphs in the British Isles have long been debated, with amateur rock art researcher Ronald Morris listing 104 different proposals that he had encountered, ranking them according to