A King's Ransom in Bronze in ancient Phrygia, near modern-day Ankara, lies a massive earthen mound known as Tumulus MM, or the "Midas Mound".%%CITE_1%% Standing over 50 meters tall, it is the largest of more than 120 burial mounds at the site of Gordion, the Phrygian capital.%%CITE_1%%%%CITE_2%% Excavations in 1957 by the University of Pennsylvania revealed an intact wooden tomb chamber, dated to around 740 BCE.%%CITE_1%%%%CITE_3%% This makes it the oldest standing wooden structure in the world.%%CITE_4%% Inside lay the remains of a king—not Midas himself, but likely his father, Gordios—along with a collection of funerary goods.%%CITE_1%%%%CITE_5%% Among the 170 bronze vessels, which included large cauldrons, drinking bowls, and pitchers, scientists discovered evidence of an advanced metalworking tradition.%%CITE_3%%%%CITE_6%%
The Phrygian smiths were masters of a specific alloy: arsenical bronze. This material is a mixture of copper and arsenic, often used before tin became the more common additive. Adding arsenic to copper creates an alloy that is harder and stronger than pure copper. Analysis of artifacts from Gordion shows a deliberate use of this alloy, with arsenic content above 1% by weight, a level that distinguishes it from accidental contamination from arsenic-rich copper ores. This choice of material provided strength. Arsenical bronze can also produce a silvery sheen on the finished object, an aesthetic quality the Phrygians may have desired. The tomb contained an array of these objects, from huge cauldrons on iron stands to 182 bronze fibulae, a type of ancient garment pin.
Hammer and Heat
Microscopic examination of the bronze artifacts from Tumulus MM shows their creation. Metallurgists use a technique called metallography, where a small sample of the metal is polished and etched to reveal its internal crystalline structure. The structure of the Gordion bronzes shows evidence of manufacturing techniques, specifically a cycle of cold-working and annealing.
Cold-working is the process of hammering metal at room temperature. This action shapes the object, but it also compresses the metal's crystal structure, making it harder and more brittle—a phenomenon called work-hardening. If the smith hammers the metal too much, it will crack. To prevent this, the smith employs annealing: heating the metal to a specific temperature and allowing it to cool slowly. This process relieves the internal stresses and softens the metal, allowing it to be worked again. The microscopic evidence for this cycle is visible in the Gordion artifacts. Scientists can see slip bands—distortions in the crystal lattice caused by hammering—alongside "annealing twins," new crystal boundaries that form during the heating process. This proves the Phrygian artisans had a deep, practical understanding of their materials, repeatedly hammering and heating the bronze to create durable and complex shapes, such as the ram-headed and lion-headed situlae (bucket-shaped vessels) found within the tomb.