No they did not have birthdays as there was no calender invented then.
(Although it is commonly called President's Day to honor both Washington and Lincoln's birthdays.) It was not invented by any president. It is a federal holiday.
There is no specific collective noun for birthdays, however a noun suitable for the situation can be used; for example a cluster of birthdays, a series of birthdays, or a respectable century of birthdays.
Birthdays = Geburtstage
Yes. If they were born, then they have birthdays.
asian rituals of birthdays?
There is no patron saint of birthdays.
In Bulgaria in place of Birthdays we celebrate.. birthdays. We also have the so called nameday (saint day), but both birthdays and namedays are celebrated.
Birthday = Geburtstag Birthdays = Geburtstage
Millions around the world.
IF there where no birthdays or months no one will be born
Birthdays of Freedom was created in 1957.