Dates are very important in the study of history. The common method that is used to divide time in History is based on Gregorian calendar.
The Gregorian calendar was named after Pope Gregory XIII who ordered its adoption in 1582. According to the Gregorian calendar, the years are numbered according to the year in which Christ was believed to have been born. The period before the birth of Christ is known as BC (Before Christ) and all the years after the birth of Christ are known as A.D (Anno Domino, meaning the year of lord).
Year zero (0) – represents the year Jesus Christ was born. It is known as Anno Domino (A.D)
Anno Domino means the year of lord.
All years before year zero (0) were called (B.C) meaning Before Christ.
The Muslims on the other hand have their own calendar. Their dating starts from Hijra, that is 622, the year when Prophet Mohammed who was born in 570A.D fled from Mecca to Medina.
In order to remove religious biasness in dividing time in History the Historians came up with terms such as:
1: C.E is the abbreviation of Common Era. This was a technique of dividing time that came into being for the sake of avoiding religious differences.
2: B.C.E is the abbreviation of Before Common Era, this came into being also because of avoiding religious differences in dating historical events.
However; all ways are historically correct. So there are no limitations of using B.C, A. D, C.E or B.C.E.
HOW TO DETERMINE DATES
Dates are instruments in the science of history historians divide dates into four ways. These ways are: -
1. Recalling past events. This means important events are remembered (recalled) e.g. droughts, floods, birth, farming, eruption of diseases etc.
2. By studying language. Some names help people to remember dates of some events e.g. ‘karafuu’ started when introduction of cloves happened in Zanzibar.
3. Chemical dating (Carbon 14). Is a scientific method of determining date. It is used in finding for remains of animals or plants which died beyond 5000 years ago. Carbon 14 is a gas found in carbon dioxide which exist in the atmosphere. It is absorbed by plant or other living organisms when died carbon 14 that has already been observed star to decay a fixed rate from the time of death
4. Geological periods. These are spans of time characterized by certain conditions and specific types of animals. E.g, there were dinosaurs on the earth during the Jurassic period.
