In Biggles Looks Back, Rodnitz was a town in the then Czechoslovakia from where Marie Janis wrote to Erich von Stalhein with a cryptic appeal for help. Both von Stalhein and later Biggles traveled to town in response to the letter in an attempt to rescue Marie from her house arrest in a castle nearby. Important locations featured in the book include:
- the Schonschloss - the ancestral home of the Janis family and where Marie was imprisoned.
- the Pension Schmon - where von Stalhein first stayed after arriving in Rodnitz, near the station
- the Cafe Wagner - where von Stalhein worked as a violinist after his money was stolen.
- the Steinhof Hotel - where Biggles and Bertie stayed on their arrival
- the Ludwigstrasse - appears to be the main street of the town. The Steinhof stands on this street.
The town also had an old church and churchyard where Biggles and von Stalhein would meet secretly. The Voltana River flowed near the town and was crossed by a bridge at the end of the Ludwigstrasse.
Rodnitz is a fictional town. The location of Rodnitz is not clearly stated but some clues can be gleaned from the text. The surrounding area is mainly forested rough country which matches the terrain of South Bohemia. The Southern region of Bohemia near the Austrian frontier also had a sizable German-speaking population--much as von Stalhein described in the book. After the war, most of the German-speaking population were expelled but the Janis family was allowed to remain because they were popular with the local people.
If the (fictional) Voltana River is modeled after the Vltava River, then this also supports the Southern Bohemia location. The Vltava runs west to east in Southern Bohemia somewhat parallel to the Austrian border to the south and later swings north towards Prague. Rodnitz also stands on a railway line. Biggles and Bertie arrived by train. Later, when Bertie was departing for London, he planned to choose either the train or a bus depending on the schedule. If Rodnitz is to be placed on a map of Southern Bohemia, it would thus be on the Vltava River somewhere on the railway line which runs along the river valley from Rybník to Lipno, one of the earliest electrified rail lines in Czechoslovakia.
The one piece of information which contradicts this is when Bertie says it is close on a hundred miles to the nearest frontier. In fact there are few places in Czechoslovakia so far from a border. The distance from Prague, deep inside the country, to the Austrian border is, for example, only around a hundred miles.
Von Stalhein mentions that there is a coach service from Rodnitz to Brozno at the Austrian border. This Brozno is definitely not the real life town of Brno, which is in Moravia, not Bohemia.
See this link of a picture of Rožmberk Castle. It is situated in South Bohemia, on the banks if the Voltava River. The town and castle has many of the features of Rodnitz. The only difference is that the river meanders heavily and is wooded along the banks. It would be hard to find a "strath" like area of flat ground to land an aircraft.