There was no single factor which led to the decline of Bronze Age cultures, and the process was erratic at best; however a significant element would appear to be the ability to smelt iron from iron ore. The earliest known successful attempts to smelt iron in Eurasia was the work of the Hittites, who heated iron ore in charcoal until it was malleable, then hammered it into tools and weapons. Other cultures had attempted to pour molten iron into molds; however the end result was a brittle tool or weapon which was of poor use. Iron tools and weapons were also developed independently in sub-Saharan Africa, all c. 1300 B.C.E. Weapons made of copper, wood and bronze were no match for iron weapons, and those who used them quickly overran their foes. The development of iron weapons is a significant factor in the success of Indo-European development in Eurasia. Additionally, tools made of iron were vastly superior, and again allowed the proliferation of those cultures who used them.
Bronze, an alloy of copper and tin, had proved more durable than either of those elements alone. However, iron proved to be even more durable and ultimately superseded the use of bronze.
One of the major factors of the fall of the Bronze Age were the devastating wars during that time period, especially during the late Bronze Age. Historical accounts suggest that the wars were as a result of continued famine caused by changing climatic conditions, which affected agriculture and food supplies. In an attempt to ensure their survival, different groups raided neighboring towns and destroyed cities in the quest for survival.
Attacks on the cities were targeted at the palaces, which were considered the centers of power and control due to the centralized nature of the administration. The system ensured that wealth was held by the ruling elite before being distributed to the masses. Thus, in times of hunger and strife, the masses directed their ire towards the ruling elite, leading to extensive destruction.
Additionally, developments in iron processing led to the phasing out of bronze items, which were replaced by iron products. Iron products were considered superior compared to bronze products especially with regards to weapons. These changes also contributed to the fall of the Bronze Age.