Some names are more common than others. There are 46,953 people named John Smith in the United States. There are 1,021 people named James Bond, 107 people named Harry Potter , 457 people named George Bush, and 33 people named Emily Dickinson.
1920 (MCMXX) was a leap year starting on Thursday (dominical letter DC) of the Gregorian calendar, the 1920th year of the Common Era (CE) and Anno Domini (AD) designations, the 920th year of the 2nd millennium, the 20th year of the 20th century, and the 1st year of the 1920s decade.
It can be omitted. Martius (March) can also be abbreviated MAR. If you want to add the year, you can add the year we would use converted into Roman numerals-so 1999 would be MCMXCIX. If you want to use a Roman year, add 753 to the year before converting into Roman and add the letters AUC at the end-so 1999 becomes MMDCCLII AUC. I don't have a conversion table for numbers this big so just take 1000 off, look that number up in my tables and then add a 'M' at the start.