Since approximately 10,000 BC, Iraq, together with a large part of the Fertile Crescent also comprising Asia Minor and the Levant, was one of centres of a Neolithic culture known as Pre-Pottery Neolithic A (PPNA), where agriculture and cattle breeding appeared for the first time in the world. The following Neolithic period, PPNB, is represented by rectangular houses. At the time of the pre-pottery Neolithic, people used vessels made of stone, gypsum and burnt lime (Vaisselle blanche). Finds of obsidian tools from Anatolia are evidences of early trade relations.