The second option ("on March the twelfth") is the most formal and old-fashioned. The construction isn't used much nowadays, but I like it.
I agree. I wonder if the fact that this form has fallen into relative disuse is the pervasiveness of using the name of a day of the week ("on Thursday the 12th", which is inevitably followed by the ever-ominous Friday the 13th) between the "on" and the "the" in such a construct rather than the name of a month.
Incidentally, I used the ordinal numerals "12th" and "13th" in my own examples because I'm honestly not sure what the accepted protocol is, or, in fact, whether there is one, for capitalizing the longhand forms "twelfth" and "thirteenth" in such contexts.
Finally, David, in the course of many years of dealing with international corporations, I have gravitated toward what I consider to be the most universally understood and and accepted protocol for writing dates, which means that I would write today's date as "22 February" (or with "February" abbreviated to "Feb" or "Fev"). The question remains how to pronounce it. I think it depends on the audience. Within these United States, I think that, when reading a report out loud, I would pronounce "22 February" as "twenty-two February" to some audiences, and as "February twenty-second" to others, depending on my understanding of the audience's expectations. I would appreciate your feedback on this.
Incidentally, quite a few things came up today that caused me to reflect on what happened on 22 February 2018.
In pace requiescat.