400 yrs ago

Yeshivos, starting their winter זמן on ר"ח חשון, the summer זמן on ר"ח אייר and  opening-up the freezer on Tu B'Shvat & Tu B'Av (Shiduchim)  goes back to at least 400 years ago.   R. Nosson Nota M'Hanover zt"l wrote a Sefer "יון מצולה" describing the Chmielnicki YM"S  period. (גזירת ת"ח ות"ט)   At the end of the Sefer, he describes the Yeshiva world of that period. Among the interesting things he writes is that the RoshYeshiva had a שמש ( Mashgiach) who made sure the בחורים are learning and not loitering the streets.    Every Thursday they had a בחינה (test). בחורים who couldn't answer correctly  were hit by the שמש with a big stick and shamed in public so they will remember to learn properly the following week.  (As absurd as it sounds, my generation grew up when this system was not yet considered abnormal) בין הזמנים started on Tu B'Shvat & Tu B'Av. The Roshei  Yeshiva & the בחורים traveled to the winter & summer fairs. At the fair, the learning was more relaxed.  Being all the Roshei Yeshiva and all their Talmidim were at the fair, it turned into a Shiduchim market. Any parent who had a son or daughter of marriageable age made sure to attend the fair. Hundreds & even thousands of Shiduchim were negotiated and arranged there.