diff --git a/src/collective/dms/thesaurus/dmskeyword.py b/src/collective/dms/thesaurus/dmskeyword.py
index 5c9eb03..2e490f2 100644
--- a/src/collective/dms/thesaurus/dmskeyword.py
+++ b/src/collective/dms/thesaurus/dmskeyword.py
@@ -7,6 +7,8 @@ from zope import schema
 from plone.dexterity.schema import DexteritySchemaPolicy
 from plone.dexterity.content import Item
 
+from plone.app.textfield import RichText
+
 from plone.supermodel import model
 
 from . import _
@@ -43,13 +45,13 @@ class IDmsKeyword(model.Schema):
         )
 
     # HN: historical note
-    historical_note = schema.Text(
+    historical_note = RichText(
         title=_(u"HN (Historical Note)"),
         required=False,
         )
 
     # SN: scope note
-    scope_note = schema.Text(
+    scope_note = RichText(
         title=_(u"SN (Scope Note)"),
         required=False,
         )