Calendar

a girl physically having her virginal blood return despite having relations, will ordinarily only last until age three and one day, however this will extend an additional month if the Jewish court adds a second month of Adar to the Calendar year

adding a second Adar to make a leap year in a shemttah year or the year after shemittah, not to increase shemittah or chadash restrictions

blowing shofar on Rosh Hashanah and taking a willow on seventh day of Sukkos, Calendar adjustments should ensure that they don’t fall out on Shabbos

Chananya tried to establish leap year from Babylon, letters sent, successful challenge against him from Israel

declaring leap year in Yehudah, Galilee, outside Israel, done by Jeremiah, Ezekiel and Baruch ben Neriah

esrog tree new year is 15th of shevat, does that date adjust to take the solar seasonal Calendar into account?

fixed Calendar limits which days holidays can fall out on

leap year can be declared if those coming to Jerusalem for Holiday need more time

leap year is only declared after Rosh Hashanah

month can only be 29 or 30 days

one of the months in the Jewish Calendar

Rosh Chodesh may not be declared too early (day 29) or too late (day 32)

Rosh Chodesh Nissan and Tishrei (Rosh Hashanah) are never 2 days except once due to a mistake

Rosh Chodesh Nissan and Tishrei (Rosh Hashanah) are never 2 days except once due to a mistake

second month of Adar can be added to accommodate those from outside Israel who are coming to Jerusalem for Pesach

two days of Holiday despite fixed Calendar, follow custom of fathers

witnesses of new month were proven false after new month was already declared, the ruling stands