The composition of bronze alloys used in antiquity varied considerably in different eras. Prior to the 4th century BCE, alloys were made-up of copper and tin in diverse proportions. In the 4th century BCE bronze
with a lead content of up to 40% was utilized.
Teophilus in the third book of his ‘De Diversibus Artis’ of the 13th century, advocates for the use of 18.7 to 26.6% of tin for the casting of bells. In Vannoccio Biringuccio’s 16th century treatise, ‘De la Pirotecnica’, he recommends bronze with a 7.4 to 10.7% tin content in order to cast figures (“per gittare figure”).
The bronze that is currently used for artistic castings is composed of 89% copper, 9% tin and 2% other metals.