Hi Chaim, I am non-denominational...i.e. not a protestant denomination, nor a Catholic.

Would you say that the apostles and Paul were non-denominational?

Your challenge is flawed because it assumes that the trinity is not intrinsic to Christian belief, but a product of "Protestant Christianity". You are attempting to steer the outcome without getting into what is intrinsic to Christianity. So, of course there were no Protestant Christians around in the first couple of centuries because that movement began with Marten Luther.

How about non-denominational Christians, like Paul and the Apostles and non-denominational Christians of today? Were the apostles around in the 1st century and Paul? Yes, they were and what they wrote, taught, and believed is the trinity...although the word itself was not used, which no-one is claiming anyway.

Sincerely,

Doug L.