A more recent theory claims that the development of iron technology was driven by the disruption of the copper and tin trade routes, due to the collapse of the empires at the end of the Late Bronze Age. These metals, especially tin, were not widely available and metal workers had to transport them over long distances, whereas iron ores were widely available. However, no known archaeological evidence suggests a shortage of bronze or tin in the Early Iron Age. Bronze objects remained abundant, and these objects have the same percentage of tin as those from the Late Bronze Age.