Ah now - the history of costume - something of a hobby horse of mine.

The himation was a big square of wool - when made of linen it was called the pharos.

The Dorian and Athenian men wore only the himation, I suppose (hope) they had the climate for it.

The chiton is equivalent to the Roman tunica, though the Greeks considered it more feminine or effeminate, I think both peoples wore it as a short sleeved garment, or something made out of two rectangles with whatever joining and gathering was the fashion at the time.

The Romans wore the pallium in the same way as the Greeks wore the himation when it was combined with the chiton, that is as an outdoor garment, though it also served as a bed cover.

The Roman pallium was as wide as the distance of the wearer's shoulder from the floor and about three times as long, and was worn by men, women and children, and both civil and military personnel.

It became characterised as the dress of the scholar and philosopher, as the sole garment, and could be the seamless mantle referred to as the garment of Christ.

There is an ecclesiastical pallium which is something worn by the Pope, which is a much reduced item, still worn wrapped around - but I think only around the neck rather like a scarf.