A new study provides detailed information about the timeline of ancient Egypt's Old, Middle and New Kingdoms using radiocarbon dating. Although much is known about the chronological order of the pharaohs who ruled ancient Egypt, the dates have remained fuzzy. By dating 211 plant samples from artifacts associated with the reigns of different kings, the study gives the most precise information to date on dozens of pharaohs. It appears in the June 18 issue of Science. For instance, the New Kingdom -- the era of King Tutankhamun and the Kings Rameses -- began between 1570 and 1544 B.C., according to the report. Previous estimates suggested the date was 1550 or 1539 B.C. The data also indicates that Djoser, a notable pharaoh of the Old Kingdom, started his reign between 2691 and 2625 B.C. Previous estimates have varied, with two widely cited sources suggesting his reign started in 2667 or 2592 B.C. 'The research agrees with the previous estimates but gives us more precise windows,' said Christopher Bronk Ramsey, an archaeologist at the University of Oxford. To conduct the study, Ramsey and his colleagues used samples from museums around the world, including the Metropolitan Museum of Art in New York. The samples came from seeds, baskets, textiles, plant stems and fruits associated with a particular reign. Most of the samples had been taken out of tombs. Previous radiocarbon dating used technology that was less precise, and coal and wood samples, which may have led to inaccurate estimates. Because resources like coal and wood were in short supply, they may have been reused over the course of different reigns, Ramsey said. In the new study, he and his colleagues focused on plant materials because of their short lifespan. 