Tvrz Václava IV.

Tvrz Václava IV. (Wenceslas IV's Fortified Manor) refers to the remains of a small medieval water fortress in Prague's Záběhlice district, built around the turn of the 15th century in connection with King Wenceslas IV. No trace of the structure is visible today — its foundations lie beneath the bed of Hamerský Pond, rediscovered only in the mid-20th century during engineering works.

Where was the fortress located?

The site sits within today's Hamerský rybník (Hamer Pond) in Záběhlice, on Prague's eastern edge. It is an unassuming spot with no plaques or visible masonry above ground, since the entire structure lies submerged beneath water and pond sediment. A visitor unaware of its history would walk past without realizing they were standing above the former residence of a King of Bohemia and Holy Roman Emperor.

Why did Wenceslas IV build here?

By the early 15th century, Wenceslas IV's political authority was weakening and he was also dealing with declining health. Monument records date the fortress to 1407–1408, though the exact founding period remains uncertain. What is documented is that the king stayed at the Záběhlice residence during those years while simultaneously overseeing construction of a new hunting castle near Kunratice. That new stronghold — known today as Nový hrad — was intended to eventually replace the less secure water fortress at Záběhlice as a more permanent royal residence.

What happened to the fortress?

The Záběhlice tvrz was a small fortification surrounded by water, with the pond itself serving as a natural defensive barrier. Historical accounts suggest the building stood for little more than a decade before its destruction: it is believed that Hussite residents of Prague demolished it around 1420, during the Hussite Wars, a period in which many structures connected to the royal court were destroyed.

How was it discovered by archaeologists?

The fortress's fate came to light only in February 1960, when the state company Vodní stavby was carrying out work on the drained Hamerský Pond. While clearing mud from the pond bed, workers found stone rubble, visible as wavy outlines of masonry and as differences in soil coloration and vegetation height across the drained bottom. An archaeological survey followed in June and July 1960, covering roughly 120 square meters — estimated at about a quarter of the original building's footprint. The excavation revealed the layout of several rooms, including a larger chamber measuring 11 by 7 meters, where part of a floor made of fired square bricks, laid diagonally to the foundation walls, had survived. Wall thickness was measured at 80–90 centimeters, with surviving masonry reaching up to 30 centimeters in height, and fired brick courses interspersed within the stonework. Finds included roof tiles, ceramic fragments, and iron objects, all dated to the turn of the 14th and 15th centuries — consistent with the chronology suggested by historical sources.

What is its status today?

On December 22, 1964, the site was entered into the state register of cultural monuments as an archaeological site. Formal protection, however, does not make it a tourist attraction in the conventional sense — the area remains part of the pond and its surroundings, with no reconstruction or above-ground display. For anyone interested in the history of medieval Prague and the later years of Wenceslas IV's reign, it is more a place for quiet reflection than a ruin to explore in the traditional sense.

Frequently asked questions

Where exactly was the Tvrz Václava IV. located? Within the grounds of today's Hamerský Pond in Prague's Záběhlice district.

When was the fortress built? Monument records date it to 1407–1408, though the precise founding date remains uncertain.

Why did the fortress cease to exist? It is believed to have been destroyed by Hussite forces around 1420, during the Hussite Wars.

Can its remains be seen today? No — the foundations were uncovered during archaeological work in 1960 but lie beneath the pond bed and are not open to visitors.