.../Drupal/Core/Block/MainContentBlockPluginInterface.php   |  2 +-
 core/lib/Drupal/Core/Block/TitleBlockPluginInterface.php    |  2 +-
 .../block/src/Plugin/DisplayVariant/BlockPageVariant.php    | 13 +++++++------
 .../page_cache/src/Tests/PageCacheTagsIntegrationTest.php   |  2 ++
 core/themes/bartik/templates/page.html.twig                 |  6 +-----
 core/themes/classy/templates/layout/page.html.twig          |  4 +---
 6 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/core/lib/Drupal/Core/Block/MainContentBlockPluginInterface.php b/core/lib/Drupal/Core/Block/MainContentBlockPluginInterface.php
index 2516348..38da7b3 100644
--- a/core/lib/Drupal/Core/Block/MainContentBlockPluginInterface.php
+++ b/core/lib/Drupal/Core/Block/MainContentBlockPluginInterface.php
@@ -10,7 +10,7 @@
 /**
  * The interface for "main page content" blocks.
  *
- * A main page content block represents the content returns by the controller.
+ * A main page content block represents the content returned by the controller.
  *
  * @ingroup block_api
  */
diff --git a/core/lib/Drupal/Core/Block/TitleBlockPluginInterface.php b/core/lib/Drupal/Core/Block/TitleBlockPluginInterface.php
index d8e6e3f..f4deff0 100644
--- a/core/lib/Drupal/Core/Block/TitleBlockPluginInterface.php
+++ b/core/lib/Drupal/Core/Block/TitleBlockPluginInterface.php
@@ -10,7 +10,7 @@
 /**
  * The interface for "title" blocks.
  *
- * A title block represents the title returned by the controller.
+ * A title block shows the title returned by the controller.
  *
  * @ingroup block_api
  */
diff --git a/core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php b/core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php
index 1ed733a..1ffa5f0 100644
--- a/core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php
+++ b/core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php
@@ -135,10 +135,11 @@ public function setTitle($title) {
    * {@inheritdoc}
    */
   public function build() {
-    // Track whether blocks showing the main content, messages and title are displayed.
+    // Track whether blocks showing the main content, title and messages are
+    // displayed.
     $main_content_block_displayed = FALSE;
-    $messages_block_displayed = FALSE;
     $title_block_displayed = FALSE;
+    $messages_block_displayed = FALSE;
 
     $build = [
       '#cache' => [
@@ -155,13 +156,13 @@ public function build() {
           $block_plugin->setMainContent($this->mainContent);
           $main_content_block_displayed = TRUE;
         }
-        elseif ($block_plugin instanceof MessagesBlockPluginInterface) {
-          $messages_block_displayed = TRUE;
-        }
         elseif ($block_plugin instanceof TitleBlockPluginInterface) {
           $block_plugin->setTitle($this->title);
           $title_block_displayed = TRUE;
         }
+        elseif ($block_plugin instanceof MessagesBlockPluginInterface) {
+          $messages_block_displayed = TRUE;
+        }
         $build[$region][$key] = $this->blockViewBuilder->view($block);
 
         // The main content block cannot be cached: it is a placeholder for the
@@ -196,7 +197,7 @@ public function build() {
     // Analogously for the page title.
     if (!$title_block_displayed) {
       $build['title'] = [
-        '#markup' => '<h1>' . $this->title . '</h1>',
+        '#markup' => $this->title,
       ];
     }
 
diff --git a/core/modules/page_cache/src/Tests/PageCacheTagsIntegrationTest.php b/core/modules/page_cache/src/Tests/PageCacheTagsIntegrationTest.php
index c6af0ac..ee610eb 100644
--- a/core/modules/page_cache/src/Tests/PageCacheTagsIntegrationTest.php
+++ b/core/modules/page_cache/src/Tests/PageCacheTagsIntegrationTest.php
@@ -95,6 +95,7 @@ function testPageCacheTags() {
       'config:block.block.bartik_main_menu',
       'config:block.block.bartik_account_menu',
       'config:block.block.bartik_messages',
+      'config:block.block.bartik_page_title',
       'node_view',
       'node:' . $node_1->id(),
       'user:' . $author_1->id(),
@@ -127,6 +128,7 @@ function testPageCacheTags() {
       'config:block.block.bartik_main_menu',
       'config:block.block.bartik_account_menu',
       'config:block.block.bartik_messages',
+      'config:block.block.bartik_page_title',
       'node_view',
       'node:' . $node_2->id(),
       'user:' . $author_2->id(),
diff --git a/core/themes/bartik/templates/page.html.twig b/core/themes/bartik/templates/page.html.twig
index 307a02b..90a7d10 100644
--- a/core/themes/bartik/templates/page.html.twig
+++ b/core/themes/bartik/templates/page.html.twig
@@ -123,11 +123,7 @@
         <main id="content" class="column main-content" role="main">
           <section class="section">
             <a id="main-content" tabindex="-1"></a>
-            {% if page.title %}
-              <h1 class="title" id="page-title">
-                {{ page.title }}
-              </h1>
-            {% endif %}
+            {{ page.title }}
             {{ title_suffix }}
             {% if tabs %}
               <nav class="tabs" role="navigation" aria-label="{{ 'Tabs'|t }}">
diff --git a/core/themes/classy/templates/layout/page.html.twig b/core/themes/classy/templates/layout/page.html.twig
index 589a0a6..7c90fbb 100644
--- a/core/themes/classy/templates/layout/page.html.twig
+++ b/core/themes/classy/templates/layout/page.html.twig
@@ -105,9 +105,7 @@
       {{ page.highlighted }}
 
       {{ title_prefix }}
-      {% if page.title %}
-+        <h1>{{ page.title }}</h1>
-      {% endif %}
+      {{ page.title }}
       {{ title_suffix }}
 
       {{ tabs }}