St. Markus, Baroque church in Sießen, Germany

St. Markus in Sießen is a monastery and parish church built from 1726 to 1729 to plans by Dominikus Zimmermann. Its pale yellow facade with white pilasters stands behind a white wall; a square clock tower with a small domed top rises on the left, and the right end closes in a curved apse. Inside, the vaulted white nave holds a high altar framed by reddish-brown marble columns with gold capitals, a golden sunburst above a painting, and dark wooden pews.

A predecessor church on the estate of Knight Steinmar von Strahlegg was taken over by the Saulgau Dominicans in 1260 and incorporated into the monastery in 1348. After the Baroque renovation of 1683–1685, Prioress Maria Josepha Baizin had a new monastery and church built; the foundation stone was laid on 4 April 1716. Franz Beer von Au began the work, and after his death in 1722 Dominikus Zimmermann took over the church, built 1726–1729. Weihbischof Franz Johann Anton von Sirgenstein consecrated it on 16 May 1733.

The church is dedicated to St. Mark, called St. Marxen in the old sources; the earlier church on the site already bore this patron. The monastery incorporated it in 1348. Inside, the vault frescoes painted by Johann Baptist Zimmermann in 1729 take the Eucharist as their theme, showing scenes from the Old and New Testaments.

The church stands within the Sießen monastery grounds in Bad Saulgau, in the Sigmaringen district. The nuns' choirs are stacked: a glazed winter choir below and a gallery-like summer choir above, with the organ behind. A restoration from 2002 to 2003 repaired the vaults and roof after cracks had formed.

The church holds a set of 1762–1763 late Rococo furnishings: the pulpit, two side altars and the high altar, whose carvers are unknown. In 1878–1883 most other Rococo fittings were removed; the diocesan vicar Georg Dengler of Regensburg dismissed them in a report as in the most tasteless and excessive Rococo style.