The Euphrasian Basilica complex, including a sacristy, baptistery and the bell tower of the nearby archbishop's palace, is an excellent example of early Byzantine architecture in the Mediterranean region. The Basilica has been inscribed on the UNESCO World Heritage List since 1997.
The earliest basilica was dedicated to Saint Maurus of Parentium and dates back to the second half of the 4th century. The floor mosaic from its oratory, originally part of a large Roman house, is still preserved in the church garden. This oratorium was already expanded in the same century into a church composed of a nave and one aisle (basilicae geminae). The fish on the floor mosaic dates from this period. Coins with the portrayal of emperor Valens (365–378), found in the same spot, confirm these dates.
The present basilica, dedicated to Mary, was built in the sixth century during the period of Bishop Euphrasius. It was built from 553 on the site of the older basilica that had become dilapidated. For the construction, parts of the former church were used and the marble blocks were imported from the coast of the Sea of Marmara. The wall mosaics were executed by Byzantian masters and the floor mosaics by local experts. The construction took about ten years. Euphrasius, holding the church in his arms, is represented on one of the mosaics on the apse, next to St. Maurus.
Following the earthquake of 1440 the southern wall of the central nave of the basilica was restored, so that in place of the windows which were destroyed, other were built in the Gothic style.
The most striking feature of the basilica are its mosaics, dating from the 6th century. The mosaics which decorate the inside and facade of the church are considered a valuable bequest of Byzantine art, and thanks to the floor mosaics and preserved writings the periods of its construction and renovation can be read.
The apsis is dominated by the marble ciborium, modelled after the one in St. Mark's in Venice, it was built in 1277 on the orders of Otto, Bishop of Poreč. The canopy, decorated with mosaics, is carried by four marble columns that belonged to the previous 6th-century ciborium. The front side of the canopy depicts representations of scenes from Mary's life, the Annunciation. In the 15th century Bishop Johann Porečanin ordered in Italy a Renaissance relief for the antependium of the altar, made of gilded silver. The polyptych of the Venetian painter Antonio Vivarini dates from the same period. The Last Supper, painted by Palma the Younger is a Baroquework.References:
First record of Kastelholma (or Kastelholm) castle is from the year 1388 in the contract of Queen Margaret I of Denmark, where a large portion of the inheritance of Bo Jonsson Grip was given to the queen. The heyday of the castle was in the 15th and 16th centuries when it was administrated by Danish and Swedish kings and stewards of the realms. Kastelhoma was expanded and enhanced several times.
In the end of 16th century castle was owned by the previous queen Catherine Jagellon (Stenbock), an enemy of the King of Sweden Eric XIV. King Eric conquered Kastelholma in 1599 and all defending officers were taken to Turku and executed. The castle was damaged under the siege and it took 30 years to renovate it.
In 1634 Åland was joined with the County of Åbo and Björneborg and Kastelholma lost its administrative status.