Piarist Monastery with the Church of the Annunciation and the Chapels of Sts. Florian and Virgin Mary, Religious monastery in Ostrov, Czech Republic.

The monastery complex lies on the western edge of Ostrov's historic town, next to the castle park, and was also called the Sacred Precinct. Its oldest building is the octagonal funeral chapel of St Anne (1644–1663), a mausoleum of the Dukes of Saxe-Lauenburg and Margraves of Baden. The single-nave Church of the Annunciation, built by Prague architect Martin Reiner and consecrated in 1674, has a separate bell tower linked by the sacristy. The chapels of St Florian and of Our Lady of Einsiedeln, with a domed lantern and onion turret, close the group.

The Piarist monastery with the Church of the Annunciation and a Latin school was founded in 1666 by Duchess Anna Magdalena, widow of Julius Henry of Saxe-Lauenburg. The site's first building, however, was the octagonal funeral Chapel of St. Anne, built 1644–1663 by Duke Julius Henry as a mausoleum for the Saxe-Lauenburg dukes and Baden margraves. The Chapel of St. Florian followed in 1692–1693, and the Chapel of the Virgin Mary of Einsiedeln closed the complex in 1710.

The Piarist college with its Latin school was founded in 1666 by Duchess Anna Magdalena, widow of Julius Henry of Saxe-Lauenburg. Boys from Ostrov and the wider area studied here, among them composer J. C. F. Fischer and physicist and chemist J. Loschmidt. The former sacristy and three halls of the monastery have housed a museum of church monuments since 2017.

The complex lies on the western edge of Ostrov's historic centre, next to the castle park, in the Karlovy Vary district. All buildings except the monastery itself are open to the public; the monastery church now hosts cultural events and a permanent exhibition on the town's history. The former sacristy and three monastery halls have held a museum of church monuments since 2017.

The complex comprises three separate religious buildings created over several generations, each reflecting the architectural styles of its construction period. This gradual expansion shows how the community's needs changed over time.