公元 You use AD in dates to indicate the number of years or centuries that have passed since the year in which Jesus Christ is believed to have been born. 公元
The cathedral was destroyed by the Great Fire of 1136 AD.
大教堂在公元1136年的大火中被付之一炬。
The original castle was probably built about AD 860.
最初的城堡可能建于公元860年左右。
The Roman Empire was divided in the fourth century AD.