The archaeological record in Egypt, Peru and the Caucasus suggests that arsenical bronze was produced for a time alongside tin bronze. At Tepe Yahya its use continued into the Iron Age for the manufacture of trinkets and decorative objects, thus demonstrating that there was not a simple succession of alloys over time, with superior new alloys replacing older ones. There are few real advantages metallurgically for the superiority of tin bronze, and early authors suggested that arsenical bronze was phased out due to its health effects. It is more likely that it was phased out in general use because alloying with tin gave castings which had similar strength to arsenical bronze but did not require further work-hardening to achieve useful strength. It is also probable that more certain results could be achieved with the use of tin, because it could be added directly to the copper in specific amounts, whereas the precise amount of arsenic being added was much harder to gauge due to the manufacturing process.