It’s commonly known that early Christians were prosecuted for centuries in the Roman empire, up to execution via damnatio ad bestias, meaning they were made to fight lions and other beasts in deadly competitions.
There are zero authentic accounts of Christian martyrdom in the Colosseum until over a century after Christianity became the official religion of the Roman Empire. In fact, not a single legitimate record exists of the Romans executing any Christians in the Colosseum. Zip. Zilch. Nada.
Now, the Friendly Atheist articles are generally well researched and thus believable, but this one is less so. For one thing, most of its references are to entirely unspecific (or not accessible) “Google Books” searches that prove nothing.
Furthermore, the claim that there are no legitimate records is directly contradicted by the Wikipedia article above, which cites several references by contemporaries, such as Tacitus and Tertullian. Another article claims that the persecution lasted three centuries and was witnessed by several historians.
All this directly contradicts the claim that “there are zero authentic accounts … until over a century after Christianity became the official religion of the Roman Empire”, because that happened after the three centuries of persecution. It also contradicts a quote taken from The Myth of Persecution: How Early Christians Invented a Story of Martyrdom (by Candida Moss, published in 2013):
… the prosecution of Christians was rare, and the persecution of Christians was limited to no more than a handful of years.