The present day name probably comes from rieses
(mediaeval Latin for "untilled lands"),
as they were in the 13th c., when the Barony of
Riesi becarne a fief of the Ventimiglias. In 1474
the fief fell to the Di Castellar family; in 1513
the husband of Eleonora Di Castellar, Giovanni Rujs
de Calcerra, obtained the licentia populandi, but
the present-day town was founded more than acentury
laterin 1647, under the Barony of Pietro Altarriba.
The town maintains the name of the ancient fief,
although some documents speak of Altariva, from
the narne of the Baron who founded the town.
The town presents, richly decorated with stuccos
and frescoes, the Chiesa Madre, Madonna della Catena,
built in the first half of the 18th c. and later
restored. Another church, San Giuseppe (19th c),
can be seen in Corso Vittorio Emanuele, in a fine
scenographic position on a hill-top.