I almost forgot about this tradition on the Feast of Sts. Peter and Paul. Pallium is Latin for shawl or whatever you call the material one puts over their shoulders. It is made of wool, and shrunk down to be a symbol of what once probably was a clock, like a king or superhero would wear.
Roman philosophers wore palliums. So did St. Justin when he was martyred in 165 AD. We next hear of it in the 6th century. Pope Gregory bestowed it on bishops he wanted to honor. By the 9th century all metropolitans were wearing a pallium.
Even today, the tradition continues. Two lambs are brought from Tre Fontane, the site of St. Paul's martyrdom, to the Basilica of St. Agnes. They are taken to the Pope, who blesses them and gives them into the care of sisters. Before Easter, these lambs are shorn and their wool is used to make the pallium.
Six black crosses are on the pallium: front, back, shoulders and bottoms. A pin called a spinula is placed on the left shoulder to keep the pallium in place. It is worn over the chasuble.
Metropolitans wear pallium. A metropolitan is a bishop over an archdiocese.
