Dates of phenomena expressed in years, or in the subdivisions thereof, consist of absolute or chronometric dates. For example, from historical documents historians established the chronometric date of the suicide of the Roman emperor Nero as June 9, 68, the day after the Roman Senate deposed him. 

The chronological date of the manufacture of the oil lamp at the right, however, is unknown. Yet, it has sufficient identifiable characteristics for archaeologists to establish a relative date. Found near Jerash (ancient Gerasa, a city of the Decapolis) the lamp’s size, shape, color, material, and the like let archaeologists identify it as belonging to the Early Roman Period (63 BCE – CE 132).

Archaeologists often provide chronometric dates in BP, that is, before the present, using 1950 as the base year for scientific convenience. An object dated 350 BP would be 400 years old in CE 2000 (1950 + 50). While several chronometric methods find specific use in biblical archaeology, e.g., potassium-argon, thermoluminescence, retentive magnetism, and the like, radiocarbon dating and dendrochronology have particular importance in dating phenomena relating to biblical times.