The Pope appeared wearing red vestments.

Literal

Pope [topic-は] red vestments [object-を] clad-[wearing-て] appeared

法王 = the Pope (literally 'law-king'; more recent news uses 教皇 — same person, different term). 法衣 = Buddhist/Catholic robe, vestment. まとう ('to be clothed in, wear') is a literary verb, more evocative than the plain 着る.