Tartt is arguably at her weakest in this minor sub-plot. The fictional 'Isrami' government belongs to a Middle-Eastern country which, if this detail concerning the heritage of its crown princess is taken literally, would coincide geographically with modern Iraq. Its history - a monarchy overthrown by an Islamic revolution - is more like that of Iran.
In the Old Testament, the Tower of Babel was built several generations after the Great Flood, when humanity was undivided, and spoke a common language. It was designed to reach up to Heaven. When God realised this he was offended, and scattered the people and separated their speech into many different languages, driving them apart so that they would never be able to achieve such a heretically ambitious bit of architecture.
The Tower of Babel has long been identified with the Etemenanki, a large ziggurat in Babylon (modern Iraq). Dedicated to Marduk, it stood seven stories high, until it was demolished by Alexander the Great in the third century B.C.