Quoting Garth Wallace <[log in to unmask]>:

> Going by the examples in the Wikipedia article on Slovene grammar, it
> seems to express purpose there. But that doesn't seem to be what it does
> in Swedish, according to Andreas. And I can't remember even talking
> about it in my high school Latin class.

That's right; the Swedish supine is no more indicative of purpose than is the
English past participle in compound tenses.

Quoting Jeff Jones <[log in to unmask]>:

> Typical Romance language sound changes would make the supine end up being
> the same as the past participle, except that it wouldn't change for gender
> or number. Apparently, someone writing, say, a Spanish grammar decided that
> the past participle in the compound tenses was really a "supine", and this
> terminology was carried over to Swedish. At least that's my theory!

That might very well be right; at least, I've never heard any other explanation.