In the Vrsar-Orsera harbour there is a very interesting medieval monument: the Romanesque basilica of St. Mary of the Sea. The basilica represents an outstanding monument of the Romanesque architecture in Istria. Its history is long and curious. In Roman times some large building (maybe "villa rustica" - a country house with farm buildings) was standing on that place. The original and modest church of St. Mary was built on that spot in the early Middle Ages (second half of the 8th century). Between the 8th and the 12th century the original church was repeatedly reconstructed. Its present-day architectural and artistic appearance is dating from the 12th century.

Traces of the reconstructions can still be seen on the walls. In recent years the church was renovated several times (last renovation in 1969). As to its architecture. the quite monumental basilica (24.5m x 12,5m) reminds of Old Christian churches. The Croatian art historian Ljubo Karaman (1881-1971) wrote about this basilica: "Vrsar-Orsera has a wide three-nave Romanesque basilica on columns. which has preserved its original impression of a church having atmosphere of simple Old Christian buildings''. The facade is pretty plain. There is a round window (oculus) on it. On the east side there is a simple belfry formed like a Romanesque monofora (one arch for the bell). In the belfry is a little bell dating from 1922. made in the bell foundry Lapagna in Triest. Semidark interior is very impressive. It is divided into three naves by heavy Romanesque arches and monolithic round columns. On each side there are three columns with interesting capitals of the Romanesque style, decorated with floral motifs (palms). The capitals are rounded off in the lower part and square on the top. Eastern part of the church interior ends in three apses.

The church floor is not original. It has been raised, therefore the columns seem to be too short. In this way the primary Romanesque harmony of the church interior has been disturbed. In the past the floor was covered with sepulchral slabs provided with Latin texts. One such slab has been preserved in the church presbytery.

Interior walls were decorated with polychromatic religious frescoes, first of which were painted in the 9th or 10th century. In the first half of the 16th century some native artist painted the interior again with high-quality frescoes. Although very poor traces have been preserved, some of the frescoes can still be seen on the main apse wall (Saints' heads). Once the basilica was equipped with a rich artistic inventory (statues, paintings etc.) Today the church looks empty and miserable. The wooden statue of the Gothic Madonna dating from the 14th century, which had belonged to this church, was stolen from the parish church of St. Martin some 20 years ago. Paintings made by old Venetian masters have also disappeared. Only the painting representing the Madonna and the Saints is still kept in the church. On it there is a signature VITORIO JERALTA. In 1177. travelling from Venice to Ancona. the pope Alexander III stayed in Vrsar-Orsera for three days and celebrated the Mass in this basilica. Next to the church there used to be an old graveyard. Some traces of it have remained by the northern backyard wall. In 1900 a new cemetery was made outside the town, by the road leading to Funtana-Fontane. In the church-yard, right of the south portal, there is a classical Roman stone block, decorated with garlands (wreaths made of leaves and fruits) hanging on the horns of ox skulls. The stone was discovered in 1932 near the small village Valkanela, not far from Vrsar-Orsera. It belonged to a Roman country house ("villa rustica") from the 12th or 13th century.

 Right by the basilica there are remains of an old monastery. In written documents the monastery was mentioned for the first time in the second half of the 12th century (1177) under the name "Prioratum Sanctae Mariae". However, it is not certain whether the monastery really existed at that time. A more reliable document dates from the year 1227. The first monks in the monastery were the Carmelites (named after the Mount Carmel in Palestina) who. persecuted by the Turks and the Arabs travelled through Cyprus and Sicily and arrived to Europe.

The Carmelites settled down in Vrsar-Orsera either at the end of the 11th century or at the beginning of the 12th century and founded their monastery here. With some interruptions the Carmelites lived in the monastery till the middle of the 14th century. In the second half of the 17th centurv (about 1631) the Franciscans came to the monastery and stayed here up to 1660. when it was closed due to a conflict between the monks and the Poreč Bishop Gianbattista de Giudice. The matter in dispute was ownership of monastery possessions (in a quarrel the monks killed the Bishop's nephew). The Franciscans renovated the old monastery building in the Baroque style. In the ground floor there were wine-press, olive-mill and store-rooms for agricultural products. After the Franciscans had left.for some time (till 1732) the seminarium (school for priests) was held in the monastery. The facade dating from the 17th century has been preserved till the present days.