How many martyrs were actually there in the event of Karbala? Why did the figure of 72 become popular when other figures are also mentioned in history?
The narrations regarding history matters are usually different, that is why you find in matters of history, deferent opinions. The most famous opinion among the historians that the number of the martyrs of Karbala is 72 martyrs.
We have other narrations in some books suggesting different numbers.
Wassalam.