In early Byzantine period Andros was an administrative part of Islands Prefecture
(capital Rodos). Christianity was spread from the first centuries to its inhabitants.
The geographical position on the main sea route towards Constantinople and
the protection needs of the empire from arab pirate attacks, made Andros an
important administration center of the Aegean Sea Province (Thema) and base
of empire customs. Accordingly was the economic and intellectual prosperity
of this period.
We know that about 820 A.C. Leon the Mathematician was instructed rhetoric,
philosophy and mathematics in Andros, studing at the same time the rich monastery
libraries of the island.
12th century, period of Komninon reign, is the best documented for the island.
Valuable sourses of information are the foreign travellers who stopped there,
on their trip to Holy Lands.
Anglosaxon Seawurf, who passed from Andros in 1204, informs us that silk industry
was the main occupation of the inhabitants. Most prized were mainly the andriotic
sixtimes-woven silk textiles. heavy and luxurious, and the fine-wooven "zentata"
and "skindalia", fine golden threads.
Despite of the general prosperity we know that enemy raids continued.Venetians,
Normands and Genoats repeatedly attacked and ravaged the place.
After the fall of Constantinople by the crusaders, Andros came in Venetian
hands. In 1207 it was given to Marino Dandolo, relative of the Doge of Venice
and stayed under their rule till 1566. In order to protect the island from consecutive
pirate attacks and the Turks, Venetians built defensive castles and towers.
First and main fort of Dandolo, military and administrative center of the Venetian
conqueror, was Mesa Kastro (Inner Castle), which was the first core of the later
Kato Kastro-Castel a basso (Lower Castle), the middle-age settlement of present
day Chora. Present name Riva comes from Venetian times, since in that area was
the main dock of Chora.
Verified byzantine churches in Andros are:
Taxiarchis in Messaria (1158)
Taxiarchis in Melida (11th century)
Taxiarchis in Ipsilou (11th century)
Panagia (Virgin Mary) in Mesathuri (12th century)
Agios Nikolaos in Korthi (12th century)
Byzantine fortifications probably existed in present day Kastro Faneromenis
(Faneromeni Castle) above Kochylou, whereas tower ruins exist up in Melida village,
as well as in the base of the small church of Agia Sofia in Pachykavos in Ormos.
The second byzantine fortification, which is considered bigger and stronger,
was Epano Kastro-Castel del alto (Upper Castle). Some coincide Epano Kastro
with present day Kastro Faneromenis, while others place it in Paleokastro area,
above Ormos. In 19th century were still visible in the area ruins of fortifications,
houses, churches, cisterns and wells.
Smaller castles and fortifications were spread all over the island. Their ruins
are visible up to date. Some of them are the Pirgos Makrotantalou (Makrotantalo
Tower), Briokastro in Varidi, Kastellaki in Gides.
During the Venetian rule also took place the settlement of Albanians, who mainly
settled in the northern part of Andros.
Venetian catalogue of 1470 reports that Andros is inhabited by 2000 people,
while ottoman report of 1567 mentions 1800 roman-greek and albanian houses and
50-60 Frank houses.