Graz — The Astronomical Codex

Your quest begins before the Landhaus, palace of the Styrian States built between 1499 and 1561. This 100-meter facade with 8 corner turrets housed the secret archives where Ferdinand II financed astronomical research. In the Renaissance courtyard, the 1557-1561 frescoes depict historical battles, but look carefully: certain details hide references to constellations that Habsburg astronomers observed from their towers. The link with astronomy reveals itself through its administrative role under the Habsburgs, who supported sciences from this center of Styrian power.

You climb Herrengasse, a noble 16th-century street 10 to 15 meters wide, paved and bordered by Renaissance houses classified as monuments. This former residence of Styrian nobility, near the Landhaus, forms a 1-km pedestrian axis toward the historic center inscribed on UNESCO since 1999. Here resided the patrons who financed secret observations, in these mansions with facades adorned with symbols only initiates could decipher. Each coat of arms, each ornamentation reveals a clue about the scientific network of the Styrian Renaissance.

Grazer Burg awaits you, a fortress built in 1240 by Ottokar II of Bohemia, residence of Styrian dukes until the 17th century. Its double helical staircase from 1532-1533, unique with two independent ramps for 260 steps, led to an informal historical observatory in the 16th century. The 20-meter-high towers integrate medieval defensive elements but also served as privileged observation points for court astronomers. Within these walls were plotted the calculations that would revolutionize European understanding of the cosmos.

The Franciscan church Franziskanerkirche, founded in 1239 and rebuilt in Gothic style in the 15th century, reveals a secret in its 55-meter length. Its 65-meter bell tower, added in 1360, served as a landmark for nocturnal observations from the Schlossberg. The tomb of Ernst Korona Fugger († 1549), financier linked to the Habsburgs and scientific patron, testifies to this church's role in the network of astronomy protectors. Integrated into the UNESCO site 'Historic Center of Graz' since 1999, it hides in its stones traces of an era when science and faith mingled under the benevolent eye of the Habsburgs.

Your journey ends atop the Schlossberg, a hill fortified since 1263 that became a 15-hectare public park accessible by 500 steps. The Uhrturm, clock tower erected in 1561, rises 28 meters with its inverted dial 3.6 meters in diameter, designed to be visible from the city. This symbol of Graz reveals its link with astronomy through its function as a precise temporal landmark since the Renaissance. From this 200-meter altitude offering a view over all Graz, you understand why Habsburg astronomers chose this site: here was hidden the true secret observatory of Styria, from where departed the calculations that led to Kepler's discoveries.