we started using bc and ad in 541.
when did we start using bc and ad?
541
Na
Na
for example, "cal 1220–1281 ad (1σ)" means a calibrated date for which the true date lies between 1220 ad and 1281 ad, with the confidence level given as 1σ, or one standard deviation. calibrated dates can also be expressed as bp instead of using bc and ad. the curve used to calibrate the results should be the latest available intcal curve. calibrated dates should also identify any programs, such as oxcal, used to perform the calibration. in addition, an article in "radiocarbon" in 2014 about radiocarbon date reporting conventions recommends that information should be provided about sample treatment, including the sample material, pretreatment methods, and quality control measurements; that the citation to the software used for calibration should specify the version number and any options or models used; and that the calibrated date should be given with the associated probabilities for each range.
radiocarbon dating