Spanish use of Roman Numerals for Centuries
This is something I learned by translating hundreds of articles in DuoLingo. In Spanish the centuries are given in Roman numerals while in English we write them out. You can see this example in many Wikipedia articles.
For example, Siglo XIX (19th century or nineteenth century) with the individual groupings of every 10 year being referred to as decades such as décades 1990 in Spanish which is the '90s in English (Provided you know the context year).
Here is a Roman numeral conversion chart I am adding to the learning resource page in the reference section. I also found some converter links. Type in the year (2014) and get the Roman numeral (MMXIV) and another for year to Roman numeral..
For example,
Roman numeral conversion 1-1000
Even better - Conversion links - just type in year or Roman numeral
2 Answers
In Mexico - maybe regional usage - we also use Roman numerals for the month in dates, ie: today is 10/XII/14
In poking around through old Spanish documents, in most cases the dates are in Roman numerals, but having said that some of the documents use conventional dating.