Perhaps the Heiligenberg’s oldest secret lies hidden just a short distance from here. This is the Bittersbrunnen. The Bittersbrunnen is a spring-fed well. It is steeped in history and mystery.
The Bittersbrunnen is located on the Heiligenberg’s northwest slope. It sits at 358 meters above sea level. That is significantly higher than the Rhine plain and Neckar valley. These surround the Heiligenberg on two sides.
This spring was likely known and used from the beginning. The Heiligenberg is the oldest and most important prehistoric settlement site on the lower Neckar. An ancient path to the hilltop passes directly by the Bittersbrunnen.
Around 1000 BC during the Urnfield culture a larger settlement existed. It was proven by numerous pottery shards. The Bittersbrunnen served as a water source. Cisterns collected rainwater as well.
Around 450 BC the Heiligenberg became the political center of the lower Neckar valley. A sprawling settlement sat on its summit. It was encircled by two ring walls. The lower ring wall curved around the Bittersbrunnen protecting it. This ensured a water supply even during sieges.
The name Bittersbrunnen may come from the Celtic word “bit”. Bit meant eternal. It does not refer to bitter water. Even during Roman and Frankish times the Bittersbrunnen remained vital. It was important during the construction of the Michaelskloster’s predecessor.
However, the spring’s flow weakened by the time the monastery was built. That was around 1023. A different spring at the Weißen Stein was tapped. Its water was piped to a well near the monastery. The Bittersbrunnen lost its central importance. Its water refreshed pilgrims and hikers.
Over centuries the Heiligenberg’s use changed. The area around the Bittersbrunnen constantly changed due to erosion and human activity. Landslides and falling trees damaged the spring.
Archaeological investigations in 1957 revealed remnants of a Romanesque well vault. A narrow water basin was discovered in front of the vault. Another basin was found 20 meters from the Bittersbrunnen. It had been filled in around the year 1000. This coincided with the construction of the water pipe from the Weißen Stein.
Below the Bittersbrunnen a thick layer of broken pottery shards was unearthed. These shards came from different centuries. Excavations reached three meters deep. Only medieval shards were found. Older finds lay deeper and were unreachable.
By the 1970s a landslide completely destroyed the Bittersbrunnen. The basin in front was buried during a forest path expansion. Reconstruction began in 1979. The area was cleared. Remains of the old spring were discovered. A new well vault with a small basin was constructed.
A pipe drains the basin under the path. The city of Heidelberg funded a third of the reconstruction costs. The state forestry office and the Heiligenberg protection association covered the rest. The spring’s flow remains weak. It barely fills the basin. The reconstructed Bittersbrunnen was inaugurated on May 3 1980.
Gold algae colonize the Bittersbrunnen. They make the basin shimmer gold in summer.
Today the Bittersbrunnen stands as a testament to time. It is a reminder of the mountain’s long history. It offers a moment of reflection. It allows us to connect with the past.