Names Of Months And The Lunar Calendar
The issue is that in semitic societies and in Judaism, the calendar which was used was luni solar. The lunar calendar was difficult for determining the actual year, however it was good for determining the start of a month which made it ideal for knowing when to begin to harvest and when to end but in terms of knowing how to calculate the year, the sun would be used as it would show the summer and winter solstice which would determine the length of the year. By using the lunar calendar alone, it is 354 years and the phases are not fully clear and based on this, the alignment of the year would be thrown off by ten days each year. In order to account for this, an additional month was added in by Jews and the Arabs in order to bring it into alignment. It makes sense that this would have dropped out of use considering it would have been done every few years. While the date is important to us in the west, many people hundreds of years ago would not have been aware of the specific time and 1400 years ago, if the alignment was affected by 10 days each year, it would have been a very slight change. This is why the words like Rabi ul awwal and Rabi Ul Thani lost their meaning because society expanded beyond an agrarian society and the harvest moon was not as important.