diff --git a/app/src/main/kotlin/de/ids_mannheim/korapxmltools/KorapXmlTool.kt b/app/src/main/kotlin/de/ids_mannheim/korapxmltools/KorapXmlTool.kt
index 739f8c7..afab174 100644
--- a/app/src/main/kotlin/de/ids_mannheim/korapxmltools/KorapXmlTool.kt
+++ b/app/src/main/kotlin/de/ids_mannheim/korapxmltools/KorapXmlTool.kt
@@ -5658,8 +5658,8 @@
             metadata["textClass"] = finalTopics
         }
 
-        headerRoot.firstText("creatDate")?.replace(".", "-")?.let {
-            metadata["creationDate"] = it
+        headerRoot.firstText("creatDate")?.let { raw ->
+            metadata["creationDate"] = normalizeKrillDate(raw) ?: raw.replace(".", "-")
         }
 
         var year: String? = null
@@ -5689,7 +5689,7 @@
             val dateVal = dateEl?.getAttribute("when")?.trim()?.takeIf { it.isNotEmpty() }
                 ?: dateEl?.textContent?.trim()?.takeIf { it.isNotEmpty() }
             if (dateVal != null) {
-                metadata["pubDate"] = dateVal
+                metadata["pubDate"] = normalizeKrillDate(dateVal) ?: dateVal
             }
         }
 
@@ -5764,6 +5764,35 @@
         }
     }
 
+    // Normalise a free-text I5 date (e.g. <creatDate> or a plain <date>) to an ISO
+    // date string (YYYY, YYYY-MM or YYYY-MM-DD), which is what Krill expects for
+    // type:date fields. Handles the canonical year-first dotted form (1932.03.03)
+    // as well as the day-first forms found in some corpora (RPK), optionally
+    // preceded by a weekday name and/or comma ("Donnerstag, 04.10.2018",
+    // "Donnerstag 05.01.2017"). Already-ISO values pass through unchanged. For a
+    // date range the first date wins. Returns null when no date is recognisable.
+    private fun normalizeKrillDate(raw: String?): String? {
+        val s = raw?.trim()?.replace(Regex("\\s+"), " ")?.takeIf { it.isNotEmpty() } ?: return null
+        fun pad(x: String) = x.padStart(2, '0')
+        // Full dates first (most specific), then year-month, then year only.
+        Regex("""\b(\d{1,2})\.(\d{1,2})\.(\d{4})\b""").find(s)?.let {       // dd.mm.yyyy
+            val (d, m, y) = it.destructured
+            return "$y-${pad(m)}-${pad(d)}"
+        }
+        Regex("""\b(\d{4})\.(\d{1,2})\.(\d{1,2})\b""").find(s)?.let {       // yyyy.mm.dd
+            val (y, m, d) = it.destructured
+            return "$y-${pad(m)}-${pad(d)}"
+        }
+        Regex("""\b\d{4}-\d{2}-\d{2}\b""").find(s)?.let { return it.value } // yyyy-mm-dd (ISO)
+        Regex("""\b(\d{4})\.(\d{1,2})\b""").find(s)?.let {                  // yyyy.mm
+            val (y, m) = it.destructured
+            return "$y-${pad(m)}"
+        }
+        Regex("""\b\d{4}-\d{2}\b""").find(s)?.let { return it.value }       // yyyy-mm (ISO)
+        Regex("""\b\d{4}\b""").find(s)?.let { return it.value }            // yyyy
+        return null
+    }
+
     private fun composeKrillPubDate(
         year: String?,
         month: String?,
diff --git a/app/src/test/kotlin/de/ids_mannheim/korapxmltools/KrillJsonGeneratorTest.kt b/app/src/test/kotlin/de/ids_mannheim/korapxmltools/KrillJsonGeneratorTest.kt
index aec8a92..bf78797 100644
--- a/app/src/test/kotlin/de/ids_mannheim/korapxmltools/KrillJsonGeneratorTest.kt
+++ b/app/src/test/kotlin/de/ids_mannheim/korapxmltools/KrillJsonGeneratorTest.kt
@@ -548,6 +548,53 @@
     }
 
     @Test
+    fun creatDateIsNormalisedToIsoForVariousI5Forms() {
+        // creatDate appears in several free-text shapes across corpora. Each must
+        // reach the Krill type:date field as an ISO date. The day-first weekday
+        // forms come from the RPK corpus; the year-first dotted form is canonical.
+        val cases = mapOf(
+            "1932.03.03" to "1932-03-03",
+            "Donnerstag, 04.10.2018" to "2018-10-04",
+            "Donnerstag 05.01.2017" to "2017-01-05",
+            "2023.03.09" to "2023-03-09",
+            "1984-01-02" to "1984-01-02",
+            // Month-only and year-only values keep their (reduced) ISO precision.
+            "2020.05" to "2020-05",
+            "2011.02" to "2011-02",
+            "2016" to "2016"
+        )
+        cases.forEach { (input, expected) ->
+            val metadata = collectKrillMetadata(
+                KorapXmlTool(),
+                "TEST_DOC.1",
+                headerElement("<idsHeader><creatDate>$input</creatDate></idsHeader>")
+            )
+            assertEquals(expected, metadata["creationDate"], "creatDate '$input' should normalise to ISO")
+            // creationDate backfills pubDate, so the document carries a clean date pair.
+            assertEquals(expected, metadata["pubDate"], "pubDate should backfill from creatDate '$input'")
+        }
+    }
+
+    @Test
+    fun creatDatePeriodsCollapseToASingleEndpointDate() {
+        // A creatDate is sometimes a period. Krill needs a single date, so we keep
+        // one endpoint (the first when the dates are uniformly formatted). Whichever
+        // endpoint is kept, it must be a valid ISO date from the period.
+        fun creationDateFor(input: String): String? = collectKrillMetadata(
+            KorapXmlTool(),
+            "TEST_DOC.1",
+            headerElement("<idsHeader><creatDate>$input</creatDate></idsHeader>")
+        )["creationDate"] as? String
+
+        // Uniformly dotted periods keep the first date.
+        assertEquals("1920-05-01", creationDateFor("1920.05.01-1923.05.02"))
+        assertEquals("2020-05", creationDateFor("2020.05-2021.06"))
+
+        // A mixed-separator period still collapses to a valid endpoint date.
+        assertContains(setOf("1920-05-01", "1923-05-02"), creationDateFor("1920.05-01-1923.05.02"))
+    }
+
+    @Test
     fun krillInheritedDatesIgnoreEmptyTextValuesAndBackfillEachOther() {
         val tool = KorapXmlTool()
         val textMetadata = collectKrillMetadata(