Philosophiae dixit:
For 8-12-2011:
I do not get sextum. It should be DuoDecimum.
I do not get octavo. It should be twelveth day of Augusti something similar to "duodecim".
I do not get Idus. Idus falls on the 13th of the month and 15th in March, May, July and October
And "sexta feria ante Assumptionem Mariae AD MMXI" needs alot of explanation.
Sorry, the American dating convention threw me out.
If you want the Roman system it is pridie, not purdie
pridie Idus Augustas MCMXXXI or prid Id. Aug. MCMXXXI
which would be duodecimo die Augusti
During the middle ages they used liturgical dating, so the sexta feria, is the Friday before the Assumption of Mary. As I said, there are many ways of writing dates in Latin, depending on which period you are looking at.
Philosophiae dixit:
For 3-21-2011:
I get A.D.=ante diem. What is B.C.?
I do not get DuoDecimum. It should be Vicesimus Primum.
I do not get Kalendas. Kalendas means the first of the month I think.
I also do not get Apriles when it is March
ante diem should be a.d.
A.D is Anno Domini. B.C. is Before Christ
The Romans counted backwards for dates, so 21 March is 12 days before the Kalends of April (using the Roman inclusive counting system)
[edit, digging out a better ref]
vicesimo primo die Martii is on the 21st day of March