Well, Guest, I don't feel like doing any research, because that would just be about other peoples' opinions. I like my own opinions, and I'll share them with you, having read the verses.

First of all, the people mentioned (Helen, Eloise and Abelard, Joan of Arc) are well-known to people who studied literature or French in college. Sydney Carter assumes you know about them as well.

Second, I think the song is tied to tourism. Sydney is touring Europe, and he's been standing on a sites associated with these famous people. You know the kind of thing: you are on a street in Paris, and somebody tells you, "This is the house where Abelard lived." Or you visit a Greek island, and they say, "This is where Helen of Troy lived."

So Sydney is thinking about these famous people and saying

"All the while they come and they go -
Where, there is no way of telling;"
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I was visiting Paris in 1999, and the guidebook said the street I was on was noted because a monk with overly-liberal views was burned at the stake there. And I thought sarcastically, "That'll cheer me up!"

Possibly Sydney had done too much touring, and the weight of human evil was weighing him down. Then he wrote this song.