„sepultus in Tyhon iuxta lacum Valatun cum suo filio David” / “he was buried in Tihany next to Lake Balaton with his son David” (excerpt from the Pozsony Chronicle)
According to the historical records, the remains of King Andrew I (†1060) and his younger son, Duke David (†1094 (?)), are to be found in the Royal Crypt of the Benedictine monastery of Tihany. Unfortunately, DNA tests have not provided sufficient evidence to separate the bones of the royal family from the other remains from the crypt, which have been mixed up over the centuries and have been severely depleted. Therefore, the researchers had to choose another method to authenticate the supposed royal remains.
After the excavations carried out in 1953, the bones found earlier in the crypt, which had not been discovered in their original position, were reburied with the newly discovered remains in 3 wooden caskets in the concrete frame created in the central tomb, on which the tombstone with a processional cross was placed on top of a few rows of bricks.
The ceremonial opening of this tomb took place as the first step in the authentication excavation of 2021. The poor quality of the wooden caskets in the middle of the tomb revealed skeletal remains that previous research had suggested were the remains of the earliest burials in the crypt. DNA analysis of the blackened, poorly preserved and fragmentary bones was carried out in parallel with the determination of their absolute age, with the assumption that the results would confirm their 11th century origin.
Radiocarbon dating
The so-called radiocarbon dating method, which can be used in archaeological research to date objects from the last 50 000 years, has provided a useful way of dating burials.
The method is based on the measurement of the current concentration of the radioactive isotope of carbon (14C), which is in equilibrium with the environment in a living organism until death, in a constant ratio with the stable isotope of carbon (12C). At the moment of death, however, this equilibrium is upset and radioactive decay becomes the dominant process, with the amount of 14C halving at regular intervals (~5700 years) and thus its concentration decreasing. Accelerator Mass Spectrometry (AMS) is the commonly used method to determine the radiocarbon age of a sample, in BP (BeforePresent), counting back from 1950. This primary data is converted into a calibrated or calendar age using the so-called calibration curve. This is denoted by the cal. term assigned to the time scale, which in our case could be given in the time elapsed since the birth of Christ (AD, or Anno Domini). For metrological reasons, the age datum obtained in this study is never a specific year (the year of death), but a larger range of up to a hundred years, within which probability values are assigned to the possible year of death. In the case of multi-sample series, the age data obtained can be further refined by mathematical models.
A few grams of bone samples from different anatomical parts, taken in parallel for DNA analysis, are lab coded. Only this coded data and the information about the sampling are sent to the laboratories carrying out the tests, i.e. the data obtained are anonymous during the test, and only at the very end are they matched with the bones. In priority cases, the analysis is carried out in parallel, starting from the same samples, in several laboratories.
The radiocarbon analysis of the bone remains recovered from Casket 2 at Tihany was carried out by several laboratories. Based on the combined data of the radiocarbon analyses carried out in Mannheim, Poznan and Debrecen in parallel, some of the bone remains recovered from Casket 2 certainly represent the earliest period of use of the crypt, the 11th century. However, it can be matched to the years of death of the king and his son from a chronological point of view only. The results obtained have well isolated the later remains, linking them to burials from the 15th to 18th centuries. The skull and skeletal remains, dated to the 11th century, may belong to the remains of King Andrew and his son Duke David.