Importance Of Heraldry

In some texts I read about Robert Guiscard, Norman conqueror of Italy, were mentioned his heraldric signs. So, was said, the lion was one of them.(Arms of Hautville family)

Than they told about the band used by the knights to put their swords on it. It was said, all the Normans have this band in their arms. All the Normans.

In Ravello I've seen arms with a lion and a band over him. I thought, it is of the family of Robert Guiscard. Asked the guides and they could not say anything about it. They said it's of Pope. But it's not true. I found a site with many arms of different Popes. All they have a mitre like this (Wikipedia):

The only sure Norman family I know lived in this zone, was the family of Princes of Salerno Sanseverino and here I found their arms in Wikipedia.
As you see, there is really a band on these arms. Nothing except it.

Where are other heraldryc signs? Like that lion of Robert Guiscard -I don't know.

Unfortunatelly I know nothing about this interesting science, Heraldry, but as it's possible to see, it is important to know it sometimes to understand ways of history.