Construction of the Dark Gate started in 1824 by Alexander Rudnay archbishop of Esztergom, two years after the foundation stones of the St. Adalbert's Basilica were laid. It got the name Dark Gate after the lack of lighting. The main purpose of the tunnel was to directly connect the Canonic houses with the Seminary, but it also connects Szentgyörgymező part of town with downtown Esztergom. Above the southern entrance a latin sign carved in red marble commemorates archbishop Rudnay and the year of construction: "PRINCEPS PRIMAS ALEXANDER A RUDNA MDCCCXXIV" - Prince primate Alexander Rudnay, 1824. From both sides of the tunnel, a huge 3700 m² wine cellar opens, where the wines of the Archdiocese of Esztergom were kept.
In the 1956 revolution this was place of main events in Esztergom. On 26 October 1956, fourteen people died when a T-34 tank shot into a bus heading towards the Seminary which was used as a Russian military facility at the time.
The Dark Gate, the seminary and its surroundings were completely renovated by 2006, the 150th anniversary of the dedication of the cathedral. Architectural lightings were added to both the basilica and the tunnel. One-way traffic is allowed from the seminary to downtown Esztergom.
Commemorative plaque with the names of people who died in 1956 in the tunnel
- Komárom-Esztergom megye műemlékjegyzéke
- Kovács László: Az 1956-os forradalom története Esztergomban