Why did Zoroastrianism, Ancient Egyptian Religions, Ancient Greek/Roman Religions and Old Norse Religions almost get totally destroyed but not Judaism?

I actually think that each of these cases must be approached individually, and that there's no hard rule which applies to all. Please bear with me, and I welcome any corrections from experts in each of these particularly.

First I'd like to address what it means for each of these religions to be destroyed. Other than the Norse, I can think of cases of each of these religions holding out far longer than the time in which they were 'eclipsed', so to speak. Jean Chardin, a frenchman who travelled through Persia in the last 17th and early 18th centuries, estimated that 40% of the population where what he called 'iranian pagans'- zoroastrians (this is over a thousand years after the islamic conquests, bear in mind). The issue is that they tended to live in marginal and rural areas, and so rather disappear from the historical and documentary record. The egyptian religion survived a while longer in the Sudan than it did in Egypt proper, where hellenistic syncretism was less of a pressure. Pamprepius and Ilus were Byzantine generals who revolted in 484 and were allegedly pagans who wanted to re-open the temples. I'm afraid I'm not aware of where the last bastion of the Norse pantheon was.

But these show that the common conception of these religions rapidly declining is a simplification, and many continued to exist well after some documentary evidence might present them as 'destroyed'. I see parallels here with what happened in the New World and the 'destruction' of native religions there.

I fall into the camp of religious change being best modelled in terms of human geography; ie there is a set of pressures to convert a people, and motives and inertia which act against those. Where we see political, economic and social factors outweighing those opposing them I would expect religious change, though the timescale is much harder to predict. In the case of Zoroastrianism, I see it strongly suggested that a major factor in the religious transformation was the conversion of local nobles to Islam for political reasons. Top-down cultural change is a powerful force which has often shaped language, culture and religion in the past and I see it as a very strong explanation here. In many periods there was also social, political, and economic persecution of Zoroastrian peoples. The source I have looked at regarding the extent of persecution is from Edward Granville Browne's A Year Among the Persians. He was very interested in the Zoroastrian traditions and viewed them somewhat romantically.

The Ancient Egyptian religion was strongly affected by Hellenistic syncretism. The Greeks had long drawn parallels between their gods and the egyptian ones, often referring to them by the name of a greek deity, and as I understand it this profoundly altered the religion of the elite in Egypt and led to them becoming part of the greater Greco-Roman religious area which was later the grounds in which Christianity rose. As for the decline of the Greco-Roman religion itself, I do not feel informed enough to speculate on the motivators at work.

So back to the question, what enabled Judaism to resist all the motivators which would draw people away from it? My perspective is that none of them were particularly strong. The Jews in Europe served an important economic function which the nobility usually wanted to preserve, and often became rich as a result. Economic and political factors pointed towards continuing the faith. Socially the segregation they endured and their tight-knit communities provided strong social pressures to remain part of their culture and faith and limited marriage outside the group. As I see it, the factors at work were simply in favour of retaining their religion.

/r/AskHistorians Thread