diff --git a/src/intermediate/footnote_definition.rs b/src/intermediate/footnote_definition.rs
index 601472b..f6da6c3 100644
--- a/src/intermediate/footnote_definition.rs
+++ b/src/intermediate/footnote_definition.rs
@@ -8,8 +8,9 @@ pub(crate) struct IFootnoteDefinition {}
 impl IFootnoteDefinition {
     pub(crate) async fn new<'intermediate, 'parse>(
         registry: &mut Registry<'intermediate, 'parse>,
-        original: &organic::types::FootnoteDefinition<'parse>,
+        original: &'intermediate organic::types::FootnoteDefinition<'parse>,
     ) -> Result<IFootnoteDefinition, CustomError> {
+        registry.register_footnote_definition(original.label, &original.children);
         Ok(IFootnoteDefinition {})
     }
 }
diff --git a/src/intermediate/registry.rs b/src/intermediate/registry.rs
index 9996893..70bb158 100644
--- a/src/intermediate/registry.rs
+++ b/src/intermediate/registry.rs
@@ -1,5 +1,6 @@
 use std::collections::HashMap;
 
+use organic::types::Element;
 use organic::types::Object;
 
 type IdCounter = u16;
@@ -7,7 +8,10 @@ type IdCounter = u16;
 pub(crate) struct Registry<'intermediate, 'parse> {
     id_counter: IdCounter,
     targets: HashMap<&'parse str, String>,
-    footnote_ids: Vec<(Option<&'parse str>, &'intermediate Vec<Object<'parse>>)>,
+    footnote_ids: Vec<(
+        Option<&'parse str>,
+        FootnoteDefinitionContents<'intermediate, 'parse>,
+    )>,
 }
 
 impl<'intermediate, 'parse> Registry<'intermediate, 'parse> {
@@ -36,7 +40,8 @@ impl<'intermediate, 'parse> Registry<'intermediate, 'parse> {
     ) -> usize {
         if let None = label {
             // If it has no label then it must always get a new ID.
-            self.footnote_ids.push((None, definition));
+            self.footnote_ids
+                .push((None, FootnoteDefinitionContents::FromReference(definition)));
             return self.footnote_ids.len();
         }
 
@@ -50,12 +55,34 @@ impl<'intermediate, 'parse> Registry<'intermediate, 'parse> {
                     .footnote_ids
                     .get_mut(existing_id)
                     .expect("If-statement proves this to be Some.");
-                entry.1 = definition;
+                entry.1 = FootnoteDefinitionContents::FromReference(definition);
             }
             existing_id
         } else {
-            self.footnote_ids.push((label, definition));
+            self.footnote_ids
+                .push((label, FootnoteDefinitionContents::FromReference(definition)));
             self.footnote_ids.len()
         }
     }
+
+    /// Update the definition to a footnote but do not mark it as referenced.
+    pub(crate) fn register_footnote_definition<'b>(
+        &'b mut self,
+        label: &'parse str,
+        definition: &'intermediate Vec<Element<'parse>>,
+    ) {
+        if let Some((existing_id, existing_definition)) = self
+            .footnote_ids
+            .iter_mut()
+            .find(|(id, _definition)| *id == Some(label))
+        {
+            *existing_definition = FootnoteDefinitionContents::FromDefinition(definition);
+        }
+    }
+}
+
+#[derive(Debug)]
+pub(crate) enum FootnoteDefinitionContents<'intermediate, 'parse> {
+    FromReference(&'intermediate Vec<Object<'parse>>),
+    FromDefinition(&'intermediate Vec<Element<'parse>>),
 }