Although this function can handle dates all the way back to the year 1 (3761 B.C.), such use may not be meaningful. The Jewish calendar has been in use for several thousand years, but in the early days there was no formula to determine the start of a month. A new month was started when the new moon was first observed.
The month as a number from 1 to 13, where 1 means Tishri, 13 means Elul, and 6 and 7 mean Adar in regular years, but Adar I and Adar II, respectively, in leap years.
The day as a number from 1 to 30. If the month has only 29 days, the first day of the following month is assumed.
The year as a number between 1 and 9999
The julian day for the given jewish date as an integer.