dates - Which acronyms are used for epochs? How are the acronyms placed?

For example, I usually use

• 560 BCE


• 1066 CE

As opposed to the traditional:

• 560 BC


• AD 1066

Some people, when using AD, place it after the year:

How are epochs commonly denoted?

Answer

Commonly, BC follows the date and AD precedes the date when referencing a specific year. Wikipedia suggests this is because English copies Latin usage of placing the abbreviation before the year number. Since AD is a latin phrase and BC is not, we arrive at 535 BC and AD 1066. Not the most compelling objective argument, I admit, but entirely plausible considering the other odd constructions we've kept around simply because of Latin tradition.

When referring to a century as a whole in text, the convention of placing either BC or AD after the stated century is considered acceptable by most of the style guides I dug up.

Wikipedia goes further to note that CE and BCE are becoming increasingly common in academic and religious writing, and suggests that CE and AD should not be used unless the date or century would be ambiguous without it.

As an aside, I remember seeing one unusual date-reference acronym that was a good five letters long. It had to do with radiocarbon years, if I recall correctly. The full acronym escapes my memory at the moment, but hopefully someone will read this and chime in.