In scientific documents published in Latin, his common name Krüger (German for potterorinnkeeper)[1] was Latinized and spelled Crüger. (Compared to the frequency of the family name Krüger, the name Crüger is relatively uncommon.)
As a philosopher and poet, Crüger was associated with the poet Johannes Plavius, who in his Institutio Poetica mentions Crüger in the opening letter. Crüger dedicated an extremely laudatory poem to Plavius, which appears in the preface to Plavius' Praecepta logicalia.
At the time of the Thirty Years' War a number of Silesians took refuge in Danzig from the ravages of war in their towns, among them Andreas Gryphius, who, when he studied at the Danzig academy from 1634 to 1636, had Crüger as a teacher[2] and was very much influenced by the famous mathematician and astronomer. Professors Crüger and Mochingert made Gryphius aware of the new style of German-language poetry. Gryphius wrote memorial verses, when in 1638 Crüger's child died. Years earlier Crüger had already developed a great friendship with Martin Opitz, "father of German poetry", who also lived in Danzig.
Crüger published treatises on many scientific subjects and contributed to the progress of trigonometry, geography and astronomy, and to the development of astronomical instruments. In the years 1627 to 1630, Crüger was the teacher of a teenager of the Hewelke family who would become known later as Johannes Hevelius, the astronomer. After Hevelius had returned to Danzig in 1634, the dying Crüger appealed[3][4] to him to pursue astronomy. Hevelius gratefully mentions Crüger in his Machina coelestis.[5]
