The following result is obtained by our Internet Research Algorithm: There were only 10 months in the ancient Roman calendar, from March to December, but as even numbers are considered to be unlucky they created 2 more months by eliminating days from other months which leads to the creation of January and February, but yes at that time also February had the 28 days hence considered being unlucky, hence decided to keep the number of days least. At that time there were believe of having 355 days in a year. Hence, Lunar calender of Romans was replaced with 365 days of solar calender and some days were added to other months. As there 365.242 days in a year, a leap day is adjusted in the month having least days i.e. February.