So here at last is an image of the recently discovered inscription.

Translated to English it reads:
"The most pious Roman emperor Flavius
Justinian and the most God-loving priest and abbot, Constantine, erected the
building in which (this mosaic) sat during the 14th indiction."
Dated by archaeologists to 550-551 CE, it is
likely that it was associated with the Nea Church that Justinian ordered to be
built in 543 CE.
Justinian could be described as the Emperor who completed the conversion of the Roman Empire to Christianity. Constantine had initiated the process, but it can be argued that the conversion of the empire was no sure thing at the time of his death. But by the time of Justinian's death the process of conversion was probably irreversible.
That's why I present this archaological find as a "reminder" of a "Christian" Jerusalem.
More information in this ABC (Australia) coverage of the story:
http://www.abc.net.au/news/2017-08-25/construction-workers-unearth-6th-century-mosaic-in-jerusalem/8841794
However just as YHWH was not powerful enough to
prevent the Romans destroying Jerusalem, neither was Jesus powerful enough to
prevent Sasanian (Iranian) forces from conquering the city in 614 with the aid
of the Jews, who then massacred tens of thousands of Christians and destroyed
Christian churches.
In 629, the Byzantian Emperor Heraclius,
re-conquered the city and the Byzantians were able to manage to hold the city
until the flood tide of Arab armies captured the city and it became an
Arabic.Muslim city.
During the Christian crusades against Islam, Jerusalem (briefly) became a "Christian" city once more, but teh Christians could not hold it against various Muslim armies. Here's how a Wikipedia entry describes the see-sawing war between Christians and Muslims
Jerusalem was conquered by the Christian First Crusade in 1099, after it had been under the Muslim rule for 450 years.

Here's how a Wikipedia entry describes that see-sawing process during the crusades.
It (Jerusalem) became the capital of the Christian Kingdom of Jerusalem, until it was again conquered by the Ayyubids in 1187. For the next forty years, a series of Christian campaigns (the Third, Fourth and Fifth Crusades) attempted in vain to retake the city, until Frederick II, Holy Roman Emperor leading the Sixth Crusade successfully negotiated its return in 1229. In 1244, the city was taken by the Khwarazmian dynasty and mostly destroyed. After 1250, it came under the rule of the Mamluk sultanate and was gradually rebuilt during the later 13th century. During those wars both sides used atrocities to attempt to demoralise the enemy,
Post WW1, the British claimed Palestine as part of the British Empire. After WW2 and the genocidal attempt by the Nazi's to exterminate European Jews. various Jewish groups used terrorist tactics to force the British out.
And today Jerusalem is (mostly) Jewish again.