diff --git a/core/lib/Drupal/Core/Path/AliasStorage.php b/core/lib/Drupal/Core/Path/AliasStorage.php
index bd027c8..72663c2 100644
--- a/core/lib/Drupal/Core/Path/AliasStorage.php
+++ b/core/lib/Drupal/Core/Path/AliasStorage.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Path;
 
+use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Database\Connection;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Language\LanguageInterface;
@@ -50,7 +51,7 @@ public function save($source, $alias, $langcode = LanguageInterface::LANGCODE_NO
 
     $fields = array(
       'source' => $source,
-      'alias' => $alias,
+      'alias' => Unicode::strtolower($alias),
       'langcode' => $langcode,
     );
 
diff --git a/core/lib/Drupal/Core/PathProcessor/PathProcessorAlias.php b/core/lib/Drupal/Core/PathProcessor/PathProcessorAlias.php
index 206e566..9e8400f 100644
--- a/core/lib/Drupal/Core/PathProcessor/PathProcessorAlias.php
+++ b/core/lib/Drupal/Core/PathProcessor/PathProcessorAlias.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\PathProcessor;
 
+use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Path\AliasManagerInterface;
 use Symfony\Component\HttpFoundation\Request;
diff --git a/core/lib/Drupal/Core/Routing/RouteProvider.php b/core/lib/Drupal/Core/Routing/RouteProvider.php
index 8f98802..d9cf01b 100644
--- a/core/lib/Drupal/Core/Routing/RouteProvider.php
+++ b/core/lib/Drupal/Core/Routing/RouteProvider.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Routing;
 
+use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Path\CurrentPathStack;
 use Drupal\Core\State\StateInterface;
 use Symfony\Cmf\Component\Routing\PagedRouteCollection;
@@ -258,7 +259,7 @@ public function getRoutesByPattern($pattern) {
   protected function getRoutesByPath($path) {
     // Filter out each empty value, though allow '0' and 0, which would be
     // filtered out by empty().
-    $parts = array_values(array_filter(explode('/', $path), function($value) {
+    $parts = array_values(array_filter(explode('/', Unicode::strtolower($path)), function($value) {
       return $value !== NULL && $value !== '';
     }));