public function renderTitle($tag = 'h1', $content = null)
    {
        if (null === $content && null !== $page = $this->getPage()) {
            $content = $page->getTitle();

            // Tags the response as Page relative
            $this->tagManager->addTags($page->getEntityTag());
        }

        if (0 == strlen($content)) {
            $content = 'Undefined title';
        }

        return $this->renderTag($tag, $content);
    }