Old St. Peter's

While Constantine wanted a distinctly Christian architecture, the New Testament says precious little about it. In light of this, there was really no choice but to turn to the Old Testament instead. And this is why to this very day if one wants to sense Jewish architecture (since the temple no longer exists) one need only look at Christian edifices.

Old St. Peter's is clearly patterned after Solomon’s Temple, not only in part corresponding to part but even its proportions.

First, the crossing of the transept (square on plan) was identified with the Holy of Holies and the nave with the Holy Place.  And both are located inside the “temple” structure, exactly as in the Jerusalem Temple.  As well, most early basilicas had an outer atrium court corresponding to the outer court of the Jerusalem Temple. 

In terms of measure, Sir Banister Fletcher's plans show that St. Peter's measured 194.57 x 64.857m on plan. This means the ground plan exactly matches the 1:3 ratio of Solomon's Temple. (No Roman measure neatly fits these dimensions, oddly.)

Moreover, in spite of the fact that archaeologists have not unearthed Peter's Tomb, Constantine did make the Aedicula ("little temple") the focus of his basilica by removing the surrounding hill and enclosing it within a square baldachin, 7 x 7m on plan.