7 long-standing historical mysteries unravelled by scientists in 2023 — and one that remains unsolved

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In 2023, scientists have used paleogenetics to uncover remarkable secrets hidden in DNA from bones and soil. They have also utilized artificial intelligence to interpret ancient texts written in forgotten languages. Through chemical analysis of molecular residues on various objects, they have revealed information about past diets, smells, and construction methods. Here are six mysteries about human history that have been solved, and one that continues to baffle researchers.

A prehistoric leader's real identity was revealed through the discovery of a 5,000-year-old skeleton in a tomb near Seville, Spain. The burial included a stunning crystal dagger and other valuable artifacts, indicating the individual's significance in ancient society.

Initially, the individual was believed to be a young man, as determined by analyzing the pelvis bone, the traditional method used by scientists to ascertain the sex of human skeletal remains. However, an examination of the tooth enamel, which contains a sex-specific peptide called amelogenin, revealed that the remains actually belonged to a female.

The technique used in other studies has also challenged the long-held stereotype of "man the hunter" that has greatly influenced ideas about early humans.

"We believe that this technique will usher in a completely new era in the study of the social structure of ancient societies," said Leonardo García Sanjuán, a prehistory professor at the University of Seville, when the discovery was announced to the public in July, as reported by CNN.

The crystal dagger was found was buried with the body of a 5,000-year-old female prehistoric leader.

Research Group ATLAS from University of Sevilla

The ingredient behind Roman concretes legendary strength

Roman concrete has been shown to outlast its modern counterpart, which can decay in just a few decades. A prime example is the Pantheon in Rome, home to the world's largest unreinforced dome.

A study published in January revealed that scientists have uncovered the secret ingredient that enabled the Romans to create such resilient construction material and erect elaborate structures in difficult environments, including docks, sewers, and earthquake-prone areas.

The study team examined ancient concrete samples dating back 2,000 years, extracted from a city wall at the archaeological site of Privernum in central Italy. These samples are comparable in composition to other concrete found across the Roman Empire.

Upon analysis, it was discovered that the white chunks present in the concrete, known as lime clasts, were responsible for the concrete's ability to self-heal cracks that developed over time. Previously, these white chunks were dismissed as indicators of substandard mixing or low-quality raw materials.

Constructed under the reign of Roman Emperor Augustus between 27 and 25 BC, Rome's Pantheon was intended to honor all the deities revered in ancient Rome. The structure underwent reconstruction during the rule of Emperor Hadrian from 118 to 128 AD.

Domenico Stinellis/AP

The actual appearance of Ötzi the Iceman

Hikers discovered Ötzi's mummified body in a high gully in the Italian Alps in 1991. His frozen remains have been extensively studied, offering unprecedented insight into life 5,300 years ago. Analysis of his stomach contents revealed his last meal and origins, while examination of his weapons indicated he was right-handed. Additionally, his clothing provided a rare glimpse into ancient attire.

A recent DNA analysis of Ötzi's pelvic DNA in August revealed that his physical appearance was not as scientists originally believed. The study of his genetic makeup showed that Ötzi the Iceman had dark skin, dark eyes, and was likely bald. This revised appearance is a significant departure from the commonly known reconstruction of Ötzi as a pale-skinned man with a full head of hair and a beard.

A close-up of the head of the 5,300-year-old frozen corpse of Ötzi in the Archaeological Museum in Bolzano.

Südtiroler Museum/picture-alliance/dpa/AP

The wearer of 20,000-year-old pendant revealed

Bone tools and other artifacts are often discovered by archaeologists at ancient sites, but it has been difficult to determine the individuals who once utilized or possessed them.

Recently, ancient human DNA was extracted from a pendant crafted from deer bone, which was uncovered in Denisova Cave in Siberia. This discovery allowed scientists to identify the wearer as a woman who lived approximately 19,000 to 25,000 years ago.

She was part of a group called the Ancient North Eurasians, who share genetic ancestry with the first Americans.

The deer bone pendant likely preserved human DNA because of its porous nature, making it more likely to retain genetic material from skin cells, sweat, and other body fluids.

The reason why the deer tooth pendant contained such a significant amount of the ancient woman's DNA (about the same amount as a human tooth) is not known. Perhaps it was cherished and worn close to the skin for an exceptionally long period, according to Elena Essel, a molecular biologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who developed a new technique to extract the DNA.

The deer tooth pendant contained DNA left by its wearer.

Max Planck Institute for Evolutionary Anthropology

AI has decoded an ancient, damaged scroll that was one of 1,100 recovered from volcanic mud nearly 2,000 years after the eruption of Vesuvius.

The Herculaneum scrolls, considered to be the largest library from classical antiquity, had their contents shrouded in mystery until a University of Nebraska computer science student, Luke Farritor, utilized artificial intelligence and computerized tomography imaging to decode a word written in ancient Greek on one of the blackened scrolls, winning a scientific contest in the process.

Farritor received $40,000 for successfully interpreting the word "πορφυρας" or "porphyras," the Greek term for purple. There is optimism among researchers that the method will soon allow for the deciphering of entire scrolls.

Hundreds of scrolls were recovered from a luxurious villa in Herculaneum, one of the Roman towns that was destroyed during the eruption of Mt. Vesuvius in 79 AD, along with Pompeii.

The materials required for mummification have been uncovered by scientists in the form of discarded pottery from an embalming workshop, revealing the substances and mixtures utilized by ancient Egyptians in the preservation of the dead.

Researchers have discovered a diverse range of substances used by ancient Egyptians for anointing the body, reducing odors, and protecting against decay through chemical analysis of organic residues found in vessels. These materials include juniper, cypress, and cedar plant oils, pistachio tree resins, animal fat, and beeswax. Despite previous knowledge of embalming substances from Egyptian texts, the exact compounds and materials remained a mystery until now.

The ingredients used in the workshop were varied and sourced not just from Egypt, but much farther afield, suggesting the long-distance exchange of goods.

An artist's reconstruction of an embalming scene with a priest in an underground chamber.

Nikola Nevenov

Beethoven: Uncovering a Family Secret, but One Mystery Remains

The renowned composer Ludwig van Beethoven passed away at the age of 56 in 1827, following a series of ongoing health issues, such as hearing loss, gastrointestinal troubles, and liver disease.

In 1802, Beethoven wrote a letter to his brothers requesting that once he died, his doctor Johann Adam Schmidt investigate the nature of his illnesses. This letter is now known as the Heiligenstadt Testament. Nearly 200 years later, scientists honored this request by extracting DNA from preserved locks of his hair.

The lock of hair from which Beethoven's whole genome was sequenced.

Kevin Brown's genetic data from Beethoven helped the researchers eliminate potential causes of his illness, such as celiac disease, lactose intolerance, or irritable bowel syndrome, although they were unable to reach a definitive diagnosis.

The genetic information also suggested an extramarital affair had taken place in the composers family.

Ashley Strickland and Taylor Nicioli contributed to this report.