diff --git a/sphinx/builders/html/__init__.py b/sphinx/builders/html/__init__.py
index 6d263a9ed..ad575c086 100644
--- a/sphinx/builders/html/__init__.py
+++ b/sphinx/builders/html/__init__.py
@@ -1243,6 +1243,10 @@ def setup(app: Sphinx) -> Dict[str, Any]:
     app.add_config_value('html_math_renderer', None, 'env')
     app.add_config_value('html4_writer', False, 'html')
 
+    # events
+    app.add_event('html-collect-pages')
+    app.add_event('html-page-context')
+
     # event handlers
     app.connect('config-inited', convert_html_css_files, priority=800)
     app.connect('config-inited', convert_html_js_files, priority=800)
diff --git a/sphinx/events.py b/sphinx/events.py
index c8d07eb61..c02d6414e 100644
--- a/sphinx/events.py
+++ b/sphinx/events.py
@@ -50,8 +50,6 @@ core_events = {
     'warn-missing-reference': 'domain, node',
     'doctree-resolved': 'doctree, docname',
     'env-updated': 'env',
-    'html-collect-pages': 'builder',
-    'html-page-context': 'pagename, context, doctree or None',
     'build-finished': 'exception',
 }