Jews and Zoroastrians

Source: H. Graetz, History of the Jews, volume II (Philadelphia: Jewish Publication Society of America, 1893) 524-526.

"On certain festivals, when the Magi worshiped light in their temple as the visible representation of God (Ahura-Mazda), the Jews were not suffered to maintain any fire on their hearths, nor to retain any light in their rooms. The Persians forced their way into the houses of the Jews, extinguished every fire and collected the glowing embers in their consecrated braziers, bringing them as an offering to their temple of fire. They also dug the corpses out of the graves, because, according to their notion, dead bodies lying in the bosom of the earth desecrated this 'Spenta Armaita' (holy soil)...Little by little, however, the fanaticism of the neo-Persians moderated, and there sprang up between them and the Jews so sincere a friendship that on their account the latter relaxed the severity of the Law, and even assisted now and then in their banquets. The teachers of the Law permitted the Jews to deliver up fuel which the Magi demanded of them on the occasion of the Festival of Light, and ceased to consider this act a furtherance of idolatry, though it would certainly have been regarded as such by the old Halacha in similar cases."

Graetz is discussing events that occurred in the third century C.E.

I should probably read up on Zoroastrianism. Did Zoroastrians worship fire? They offered fire to their god, so how's one offer a god to a god? Did they believe that corpses defile the soil? If so, then what did they do with dead bodies? Were they like the Jews, who buried corpses outside of the holy city of Jerusalem?

I vaguely remember reading a midrash that said there were pagans who thought that the Jews worshipped fire. After all, there are passages in the Hebrew Bible where God appears in a fire--the burning bush story, etc. Does that relate in any way to why Jews and Zoroastrians came to get along together?