Origin of the phrase "Oh, Dear!"

Solution 1:

Two possibilities I can think of. Firstly, it could be a contraction of:

Oh, Dear god!

to avoid blasphemy. This makes sense as it is an admonishment.

Or the other possibility is that 'Dear' was another name for god, like 'the Almighty' or 'the Lord', possibly as a result of the contraction mentioned above.

It crops up rather a lot in Patrick O'Brian's Aubrey/Maturin novels (brilliant on many levels, not least their meticulously researched use of early 19th century language), in phrases like:

"The Dear only knows that you've been working awfully hard."

Solution 2:

Apparently the interjection dates from the 1690s.

Edit: Upon further review, it appears to be a contraction of "Dear Lord!" — an expression of surprise or amazement in the form of a supplication.

Also removed the misleading attribution about unknown origin.