diff --git a/core/lib/Drupal/Core/Path/AliasStorage.php b/core/lib/Drupal/Core/Path/AliasStorage.php
index 899c39e..9732cc8 100644
--- a/core/lib/Drupal/Core/Path/AliasStorage.php
+++ b/core/lib/Drupal/Core/Path/AliasStorage.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Path;
 
 use Drupal\Core\Cache\Cache;
+use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Database\Connection;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Language\LanguageInterface;
@@ -59,7 +60,7 @@ 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 d7bd416..ebad3ab 100644
--- a/core/lib/Drupal/Core/PathProcessor/PathProcessorAlias.php
+++ b/core/lib/Drupal/Core/PathProcessor/PathProcessorAlias.php
@@ -7,6 +7,8 @@
 
 namespace Drupal\Core\PathProcessor;
 
+use Drupal\Component\Utility\Unicode;
+use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Path\AliasManagerInterface;
 use Drupal\Core\Render\BubbleableMetadata;
 use Symfony\Component\HttpFoundation\Request;
diff --git a/core/lib/Drupal/Core/Routing/RouteCompiler.php b/core/lib/Drupal/Core/Routing/RouteCompiler.php
index 1d223ff..892422a 100644
--- a/core/lib/Drupal/Core/Routing/RouteCompiler.php
+++ b/core/lib/Drupal/Core/Routing/RouteCompiler.php
@@ -51,7 +51,7 @@ public static function compile(Route $route) {
       $num_parts,
       // These are the Symfony compiled parts.
       $symfony_compiled->getStaticPrefix(),
-      $symfony_compiled->getRegex(),
+      $symfony_compiled->getRegex() . 'i',
       $symfony_compiled->getTokens(),
       $symfony_compiled->getPathVariables(),
       $symfony_compiled->getHostRegex(),
diff --git a/core/lib/Drupal/Core/Routing/RouteProvider.php b/core/lib/Drupal/Core/Routing/RouteProvider.php
index 278b486..04e5284 100644
--- a/core/lib/Drupal/Core/Routing/RouteProvider.php
+++ b/core/lib/Drupal/Core/Routing/RouteProvider.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Routing;
 
 use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Path\CurrentPathStack;
 use Drupal\Core\PathProcessor\InboundPathProcessorInterface;
 use Drupal\Core\State\StateInterface;
@@ -300,7 +301,7 @@ 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 !== '';
     }));