We mourn during sefira for the talmidim of r. akiva. However, these practices only began at the end of the Gaonic period some 800 years after the episode. Why didn't the chachamim institute the aveilus at the time it happened? Why did klal yisroel "wake up" to this after such a long time?
yosef eisen, pittsburgh pa 15217
The Teshuvos Geonim (Sharei Teshuvah #278) says clearly that ever since Rebbi Akiva's Talmidim died there has been a custom not to get married during that time. It therefore stands to reason that there probably were other various customs refraining from Simchah as well, perhaps many of our customs that we have today during Sefirah. You might ask why this would not be recorded in the Gemara. However, being that these were merely customs which might not have been uniform in every place, it is possible that it wasn't mentioned.
Alternatively, it is possible that it didn't have to be mentioned as it was known to everyone.
All the best,
Yaakov Montrose