Today's conventional conversion of 11th September 2009 into Roman numerals is XI-September-MMIX whether or not the Romans themselves did it this way is questionable.
November 11th 2009 can also be written as 11-11-2009 which is written in Roman numerals as XI.XI.MMIX
The date November 11th 2009 can also be written as 11-11-2009 and in Roman numerals this can be written as XI.XI.MMIX
II-XI-MMIX
The date September 23rd 2009 can also be written as 09-23-2009 and this can be represented by the Roman numerals IX.XXIII.MMIX
November is the 11th month. The number 11 as a Roman numeral is XI and the number 2009 is MMIX.
November 11th 2009 can also be written as 11-11-2009 which is written in Roman numerals as XI.XI.MMIX
The date November 11th 2009 can also be written as 11-11-2009 and in Roman numerals this can be written as XI.XI.MMIX
II-XI-MMIX
The date September 23rd 2009 can also be written as 09-23-2009 and this can be represented by the Roman numerals IX.XXIII.MMIX
November is the 11th month. The number 11 as a Roman numeral is XI and the number 2009 is MMIX.
5-11-2009 or May 11th, 2009. Or 5 November 2009
IX-XIX-MMIX
IX/IV/MMIX
IX-II-MMIX
Today's conventional conversion of 20th September 2009 into Roman numerals is XX-September-MMIX.However, there is strong evidence to support the fact that the Romans themselves would have written the above date as XX-September-MMVIIII.
To convert January 11, 2009 into roman numerals, you can break it down into separate numbers and convert them individually. January is the first month, so it is represented by "I". 11 is represented by "XI". Finally, 2009 is represented by "MMIX". Putting it all together, January 11, 2009 in roman numerals is "I XI MMIX".
As you asked this question on 15th September 2009, which can also be written as 15-09-2009, this date in Roman numerals would be XV.IX.MMIX