CA
“The Gemara in Rosh Hashanah says that Tishrei is Rosh Hashanah for non Jewish kings so when referring to a Jewish king reign it would be the 11th month”
IT wouldn’t
(I have a pending post which is similar, here i think I phrase it better, and provide two rayahs)
If you look at the Gemara there (actually earlier when discussing Nissan)the Gemara asks
Maybe the Aron’s death that occurred in “chodesh hachmishi” of the 40th year occurred after “chodesh ha’ashtei assar” of the 40th year.
Clearly the numbers of the month don’t have any relevence to their position in the year.
If the year started in Tishrei then yes The 11th month (shevat) would come before the 5th (Av).
Similarly The Gemara asks Daniel makes mention of the 6th month of the second year of Daryavesh then the Seventh month of the second year of Daryavesh.
IF King’s years start in Tishrei it should say Seventh month of the THIRD year.
Please note the Gemara does not say it should say the FIRST month of the THIRD year. Tishrei is the seventh month period. but if new years start in Tishrei then the month follwoing 6th month of the second year should be 7th month of the Third year? Gemara answers Daryavesh was tzadik so count from Nissan like Jewish kings .
But again if Daryavesh DID count from Tishrei . Tishrei would still be “chodesh hashvii”