In fact neither 3/12/1570 nor 12/3/1570 is recommended (see the link I cited above), though they both do seem to work.
12-3-1570 and 3-12-1570 are both permitted, but this is unfortunate and likely to lead to errors, because they are interpreted in American terms with the month first, and are ambiguous given that the rest of the world puts the day first.