Originally Posted by JemyM
The idea about Christian Persecutions go back to a tome by Eusebius known as "Acts of the Martyrs". Needless to say, this tome have been heavily analyzed and today it should be taken with a grain of salt as it's more political propaganda to justify the new church (4th century) than actual history. Many times the supposed persecutions probably never happen, or were carried out against Jews, not Christians. This piece of history can partially be seen as an extension of the religious beliefs in the religion itself.
I would recommend a Bart D Ehrman lecture on this known as "From Jesus To Constantine - A History Of Early Christianity".