You may already know the legend of King Tutankhamen's space dagger – an iron weapon forged from the rock of meteorites, and entombed with the ancient Egyptian pharaoh.
Now a new study has revealed more details about this most fascinating and mysterious of artifacts.
A thorough chemical analysis involving high-resolution photography and X-rays has revealed the type of meteorite that the dagger was most likely forged from, as well as the process used to make it.
What's more, it seems that the object wasn't made in Egypt at all, but was rather presented as a gift to King Tut or one of his ancestors.
Perhaps most significant is the discovery of a so-called Widmanstätten pattern on the dagger, indicative of the long nickel-iron crystals found in octahedrite iron meteorites, the most common type of iron meteorites.
"To understand the manufacture and origin of the dagger, we conducted on-site non-contact, non-destructive two-dimensional chemical analysis for the dagger," planetary scientist Tomoko Arai, from the Chiba Institute of Technology in Japan, told Gizmodo.
"We noticed a cross-hatched texture present in places for the both sides [of the dagger], suggesting Widmanstätten structure, typical of [an] octahedrite iron meteorite. That was our WOW moment."
For that pattern to be retained, a relatively low temperature forging technique was most likely used to mold the weapon. The researchers think that the dagger was crafted at temperatures under 950 degrees Celsius (1,742 degrees Fahrenheit) – much higher than that, and the pattern would've disappeared.
This origin story for the object is backed up by the black spots on the blade and inside a crack on the blade's surface. These sulfur-rich areas are most likely caused by the heating up of troilite, an iron sulfide mineral found in iron meteorites.
As for the chemical composition of the hilt, the analysis reveals that the decorative stones were most likely fixed with lime plaster, not a process that was commonly adopted in Egypt until much later in history. That means the dagger most likely came from elsewhere.
The researchers point out that the Amarna letters might give us some clues here: these important clay tablets dating from around 1360-1332 BCE are a collection of ancient Egyptian diplomatic correspondence, and mention an iron dagger given to one of Tutankhamen's ancestors as a present.
"[The] gold hilt hints at [the dagger's] foreign origin, possibly from Mitanni, Anatolia, as suggested by one of the Amarna letters saying that an iron dagger with gold hilt was gifted from the king of Mitanni to Amenhotep III, the grandfather of Tutankhamen," the researchers write in their paper.
This idea that the dagger came from outside Egypt has been suggested before, but now we have more proof. Further studies should be able to establish whether this is indeed a family heirloom passed down through the generations.
Before the Iron Age and its associated technologies were developed, most iron artifacts were most likely forged from meteorite fragments that had dropped from space. This would not have been a straightforward process, and most likely involved plenty of trial and error.
Tsutomu Saito, professor of cultural properties science at the National Museum of Japanese History in Japan, was not part of the current study, but has worked on previous research into iron forging that predates the Iron Age.
"[The study] provides evidence that ancient people had achieved the conditions that we predicted scientifically," Saito told the Asahi Shimbun, suggesting that the forgers of the time used both instinct and experience to find the right temperatures to craft their goods.
"This is an important finding that shows the starting point of mankind's quest to develop iron manufacturing technology."
The research has been published in Meteoritics & Planetary Science.