For over 30 years he was in the service of the Ernestine branch of the Wettin family. A letter addressed to John Frederick I dating from 1536 is the earliest written proof of Gromann's service. The letter was signed as "stonemason" . His teachers were Konrad Krebs and Andreas Günter, whose work he continued. While his first residence was located in Weida, Gromann referred to Gotha as his home in 1544. Six years later, in 1550, Gromann moved to Weimar where he built his own house. In order to move back to Gotha, he sold it in 1563. A few years earlier, in 1553 Gromann had been allocated some acres of farmland in Gotha by John Frederick I. It was also the Elector of Saxony who appointed Gromann as master builder for life. Gromann first received special attention when he built the first Protestant church, the chapel at Schloss Hartenfels in Torgau, in the period from 1543 to 1544. The "Emperor's Room" church was added skillfully into the medieval structure. Luther sanctified the church in person upon completion. The model of the Torgau Castle Church formed the basis for the designs of the castle chapels of protestant princes in Dresden, Schwerin, Stettin, Heidelberg and Augustusburg. In 1552 Gromann applied a similar design to the chapel of the castle Grimmenstein, which unfortunately was not preserved. Gromann supervised many construction sites in the Ernestine duchies. In addition he built castles, town halls, churches, fortifications, roads, bridges and fountains. Nikolaus Gromann is credited with introducing of renaissance design to the Ernestine duchies. In his early work he expressed this by adding decorative renaissance ornaments to gothic buildings. In his late work he constructed buildings in the renaissance style, which are considered his masterpieces: the Town Hall in Altenburg, the "new buildings" in Weimar, the Green Castle and the French Building of the Veste Heldburg. Gromann implemented his design for the bay windows in the living apartments of the elector on the north wing of the Castle Torgau and at the Französischer Bau of the Veste Heldburg. Today, the two bay windows are called the "Men's bay window" and "Women's bay window". His design of the Gera town hall could not be finished by himself. The project was continued by Nikolaus Theiner in 1573.
Buildings
1536/37 Conversion of Osterburg of Weida
1543-1545 Schloss Hartenfels and the church of the palace in Torgau, together with Kunz Krebs, Gromann built the north wing of the castle and the palace church, which was the first Protestant church
1548-1552 Hunting lodge "Happy Return" in the forest of Wolfersdorf
1555-1557 expansion and strengthening of the castle walls of Schloss Herbsleben
1557-1559 Colleges in Jena
1560 Old Castle of Dornburger castles in Dornburg / Saale
1560-1564 expansion of the Veste Heldburg, construction of the French building of the fortress in the Heldburg and construction of the 114 meter deep castle well
1562 Rathaus in Altenburg
1563 reconstruction of the Leuchtenburg near Kahla
1573-1576 Rathaus in Gera, designed by Grohman, construction by Nikolaus Theiner
Secondary literature
Lutz Unbehaun: Nikolaus Gromann und der Schlossbau unter den Ernestinern im 16. Jahrhundert.. In: Heiko Laß : Von der Burg zum Schloss. Landesherrlicher und Adeliger Profanbau in Thüringen im 15. und 16. Jahrhundert. 2001, S. 133-150.
Norbert Klaus Fuchs: Das Heldburger Land–ein historischer Reiseführer ; Verlag Rockstuhl, Bad Langensalza 2013,