diff --git a/src/Serval/src/Serval.DataFiles/Controllers/CorporaController.cs b/src/Serval/src/Serval.DataFiles/Controllers/CorporaController.cs
index 7e78ab2b..07c0c41a 100644
--- a/src/Serval/src/Serval.DataFiles/Controllers/CorporaController.cs
+++ b/src/Serval/src/Serval.DataFiles/Controllers/CorporaController.cs
@@ -157,6 +157,8 @@ private async Task AuthorizeAsync(string id, CancellationToken cancellationToken
 
     private async Task<Corpus> MapAsync(CorpusConfigDto corpusConfig, string id, CancellationToken cancellationToken)
     {
+        if (corpusConfig.Language == null || corpusConfig.Language.Length == 0)
+            throw new InvalidOperationException("Corpus must have a language.");
         return new Corpus
         {
             Id = id,