Historians believe that the earliest pottery wares were hand-built and fired in bonfires. Firing times were short but the peak-temperatures achieved could be high. Clays tempered with sand, grit, crushed shell or crushed pottery were often used to make bonfire-fired ceramics because these additives provided an open body texture that allowed water and other volatile components of the clay to escape freely. The coarser particles in the clay also restrained shrinkage during the slow cooling process. The earliest intentionally constructed kilns were pit-kilns or trench-kilns; holes dug in the ground and covered with fuel. Holes in the ground provided insulation and resulted in better control over firing.
The earliest known ceramic objects are figurines such as those discovered at Dolni Vestonice in the modern-day Czech Republic. The Venus of Dolni Vestonice is a nude female figure made of clay and bone ash, measuring 4.5 inches in height, dated to between 35,000 - 25,000 BC. According to archaeological evidence, the Incipient Jōmon people of Japan may have created the first known pottery vessels approximately 13,000 years ago. Artisans created hand-built pots for food storage or preparation and decorated them by rolling a rope over their damp surfaces before firing. The antiquity of this work was first identified through radiocarbon dating methods.