Fomenko specifically points to a break of dendrochronological scales around AD 1000. A date of around 1516 has been established by means of dendrochronological research. Dendrochronological or Tree ring dates indicate it was built between 1559 and 1561. However, dendrochronological analysis provided more accurate dating. Results of dendrochronological studies imply prolonged periods of drought between the 14th and 15th centuries. Age of the "Chrobry" is about 760 years, according to dendrochronological research. The dendrochronological equation defines the law of growth of tree rings. Following dendrochronological dating it was found to have a Neolithic date of 2739 BC. The nave is mostly original, and dendrochronological research in the 1960s dated it to 845. For the period back to 12,400 B.P., the radiocarbon dates are calibrated against dendrochronological dates. A Dendrochronological sample extracted from the stump was sent for analysis at Sheffield University. Dendrochronological analysis of the Philadelphia panel dated its growth rings to between 1225 and 1307. If so, a dendrochronological dating may be based upon a log from a later reconstruction.