What kind of Roman cross was used to crucify Jesus? Possible Duplicate:
  Crucifixion &mdash; torture stake or cross?  




Apparently there were at least three kinds of crosses used by the Romans to crucify criminals. One was called ‘Crux decussate’ in the shape of an ‘X’. The second, Crux Commissa, in the form of a ‘T’. Finally, they used, the Crux immissa in the form of a small 't' like what we usually see in the movies, typcical church crucifixes, or on jewelry, etc.

Is there any ancient records of the symbol of the cross in church history that would indicate what type of cross the Romans actually used to crucify Christ? 

I ask this trivia type question only because this is the type of thing my older Sunday school kids will throw at me and I have no answer.
The Biblical evidence is a bit ambiguous in this particular case, but tradition definitely says that it was cross in the shape of a small t, the common one found in classical and medieval art. Some thoughts from the Catholic Encyclopedia:
It states the cross shape explicitly:

The cross on which Jesus Christ was nailed was of the kind known as immissa, which means that the vertical trunk extended a certain height above the transverse beam

First, Biblical proof that it could not have been an &quot;X&quot;:

We gather as much from St. Matthew (27:37), where he tells us that the titulus, or inscription containing the cause of His death, was placed, &quot;over&quot;, the head of Jesus Christ

And then confirmation that it was a &quot;✝&quot; with historical evidences:

St. Irenæus (Adv. Haer., II, xxiv) says that the Cross had five extremities: two in its length, two in its breadth, and the fifth a projection (habitus) in the middle
Nonnus confirms the statement that Jesus Christ was crucified on a quadrilateral cross.

Interestingly, there seems to have been a seat for Christ as well (that fifth extremity).

St. Irenæus... says that the Cross had a fifth extremity, on which the Crucified One was seated

But, the foot support probably wasn't there:

[That] the Crucifixion there [was] a wooden support... is very doubtful.