Rollo now granted parts of Normandy to his leading men on condition
that they would bring soldiers to his army and fight under him.
They became his vassals, as he was the king's vassal.

The lands granted to vassals in this way were called feuds, and
this plan of holding lands was called the Feudal System.

It was established in every country of Europe during the Middle
Ages.

The poorest people were called serfs. They were almost slaves and
were never permitted to leave the estate to which they belonged.
They did all the work. They worked chiefly for the landlords, but
partly for themselves.

Having been a robber himself, Rollo knew what a shocking thing it
was to ravage and plunder, and he determined to change his people's
habits. He made strict laws and hanged robbers. His duchy thus
became one of the safest parts of Europe.

The Northmen learned the language of the Franks and adopted their
religion.

The story of Rollo is especially interesting to us, because Rollo
was the forefather of that famous Duke of Normandy who, less than a
hundred and fifty years later, conquered England and brought into
that country the Norman nobles with their French language and
customs.