diff --git a/actions/DisplayAction.php b/actions/DisplayAction.php
index 99dd21ce..52853d36 100644
--- a/actions/DisplayAction.php
+++ b/actions/DisplayAction.php
@@ -244,8 +244,14 @@ class DisplayAction extends ActionAbstract {
 			$format = $formatFac->create($format);
 			$format->setItems($items);
 			$format->setExtraInfos($infos);
-			$format->setLastModified($cache->getTime());
-			$format->display();
+			$lastModified = $cache->getTime();
+			$format->setLastModified($lastModified);
+			if ($lastModified) {
+				header('Last-Modified: ' . gmdate('D, d M Y H:i:s ', $lastModified) . 'GMT');
+			}
+			header('Content-Type: ' . $format->getMimeType() . '; charset=' . $format->getCharset());
+
+			echo $format->stringify();
 		} catch(Error $e) {
 			error_log($e);
 			header('Content-Type: text/html', true, $e->getCode());
diff --git a/docs/08_Format_API/02_FormatInterface.md b/docs/08_Format_API/02_FormatInterface.md
index 28ac60b3..88448c38 100644
--- a/docs/08_Format_API/02_FormatInterface.md
+++ b/docs/08_Format_API/02_FormatInterface.md
@@ -14,14 +14,6 @@ Find a [template](#template) at the end of this file
 
 # Functions
 
-## The `display` function
-
-The `display` function shows the contents to the user and must return the object instance.
-
-```PHP
-display(): self
-```
-
 ## The `stringify` function
 
 The `stringify` function returns the items received by [`setItems`](#the-setitem-function) as string.
@@ -109,12 +101,6 @@ class MyTypeFormat implements FormatInterface {
         return ''; // Return items as string
     }
 
-    public function display(){
-        // Implement your code here
-        echo $this->stringify();
-        return $this;
-    }
-
     public function setItems(array $items){
         $this->items = $items;
         return $this;
diff --git a/docs/08_Format_API/03_FormatAbstract.md b/docs/08_Format_API/03_FormatAbstract.md
index 82e42718..8cf0418f 100644
--- a/docs/08_Format_API/03_FormatAbstract.md
+++ b/docs/08_Format_API/03_FormatAbstract.md
@@ -1,27 +1,9 @@
 The `FormatAbstract` class implements the [`FormatInterface`](../08_Format_API/02_FormatInterface.md) interface with basic functional behavior and adds common helper functions for new formats:
 
-* [setContentType](#the-setcontenttype-function)
-* [callContentType](#the-callcontenttype-function)
 * [sanitizeHtml](#the-sanitizehtml-function)
 
 # Functions
 
-## The `setContentType` function
-
-The `setContentType` function receives a string defining the content type for the HTML header and must return the object instance.
-
-```PHP
-setContentType(string): self
-```
-
-## The `callContentType` function
-
-The `callContentType` function applies the content type to the header data and must return the object instance.
-
-```PHP
-callContentType(): self
-```
-
 ## The `sanitizeHtml` function
 
 The `sanitizeHtml` function receives an HTML formatted string and returns the string with disabled `<script>`, `<iframe>` and `<link>` tags.
diff --git a/formats/AtomFormat.php b/formats/AtomFormat.php
index 62ab3818..81aaf441 100644
--- a/formats/AtomFormat.php
+++ b/formats/AtomFormat.php
@@ -156,14 +156,6 @@ EOD;
 		return $toReturn;
 	}
 
-	public function display(){
-		$this
-			->setContentType(self::MIME_TYPE . '; charset=' . $this->getCharset())
-			->callContentType();
-
-		return parent::display();
-	}
-
 	private function xml_encode($text){
 		return htmlspecialchars($text, ENT_XML1);
 	}
diff --git a/formats/HtmlFormat.php b/formats/HtmlFormat.php
index b9a7aba1..b3f02099 100644
--- a/formats/HtmlFormat.php
+++ b/formats/HtmlFormat.php
@@ -137,14 +137,6 @@ EOD;
 		return $toReturn;
 	}
 
-	public function display() {
-		$this
-			->setContentType(self::MIME_TYPE . '; charset=' . $this->getCharset())
-			->callContentType();
-
-		return parent::display();
-	}
-
 	private function buildButton($format, $query) {
 		return <<<EOD
 <a href="./?{$query}"><button class="rss-feed">{$format}</button></a>
diff --git a/formats/JsonFormat.php b/formats/JsonFormat.php
index f0aa0e65..90bae863 100644
--- a/formats/JsonFormat.php
+++ b/formats/JsonFormat.php
@@ -122,14 +122,6 @@ class JsonFormat extends FormatAbstract {
 		return $json;
 	}
 
-	public function display(){
-		$this
-			->setContentType(self::MIME_TYPE . '; charset=' . $this->getCharset())
-			->callContentType();
-
-		return parent::display();
-	}
-
 	private function isHTML($text) {
 		return (strlen(strip_tags($text)) != strlen($text));
 	}
diff --git a/formats/MrssFormat.php b/formats/MrssFormat.php
index 8bf569ae..0c51104a 100644
--- a/formats/MrssFormat.php
+++ b/formats/MrssFormat.php
@@ -150,14 +150,6 @@ EOD;
 		return $toReturn;
 	}
 
-	public function display(){
-		$this
-			->setContentType(self::MIME_TYPE . '; charset=' . $this->getCharset())
-			->callContentType();
-
-		return parent::display();
-	}
-
 	private function xml_encode($text){
 		return htmlspecialchars($text, ENT_XML1);
 	}
diff --git a/formats/PlaintextFormat.php b/formats/PlaintextFormat.php
index 5a0522cf..a1ef9e7f 100644
--- a/formats/PlaintextFormat.php
+++ b/formats/PlaintextFormat.php
@@ -21,12 +21,4 @@ class PlaintextFormat extends FormatAbstract {
 		$toReturn = mb_convert_encoding($toReturn, $this->getCharset(), 'UTF-8');
 		return $toReturn;
 	}
-
-	public function display(){
-		$this
-			->setContentType(self::MIME_TYPE . '; charset=' . $this->getCharset())
-			->callContentType();
-
-		return parent::display();
-	}
 }
diff --git a/lib/FormatAbstract.php b/lib/FormatAbstract.php
index cbc7dc97..5514b0b5 100644
--- a/lib/FormatAbstract.php
+++ b/lib/FormatAbstract.php
@@ -24,9 +24,6 @@ abstract class FormatAbstract implements FormatInterface {
 	/** MIME type of format output */
 	const MIME_TYPE = 'text/plain';
 
-	/** @var string|null $contentType The content type */
-	protected $contentType = null;
-
 	/** @var string $charset The charset */
 	protected $charset;
 
@@ -65,18 +62,6 @@ abstract class FormatAbstract implements FormatInterface {
 		return is_null($charset) ? static::DEFAULT_CHARSET : $charset;
 	}
 
-	/**
-	 * Set the content type
-	 *
-	 * @param string $contentType The content type
-	 * @return self The format object
-	 */
-	protected function setContentType($contentType){
-		$this->contentType = $contentType;
-
-		return $this;
-	}
-
 	/**
 	 * Set the last modified time
 	 *
@@ -87,34 +72,6 @@ abstract class FormatAbstract implements FormatInterface {
 		$this->lastModified = $lastModified;
 	}
 
-	/**
-	 * Send header with the currently specified content type
-	 *
-	 * @throws \LogicException if the content type is not set
-	 * @throws \LogicException if the content type is not a string
-	 *
-	 * @return void
-	 */
-	protected function callContentType(){
-		if(empty($this->contentType))
-			throw new \LogicException('Content-Type is not set!');
-
-		if(!is_string($this->contentType))
-			throw new \LogicException('Content-Type must be a string!');
-
-		header('Content-Type: ' . $this->contentType);
-	}
-
-	/** {@inheritdoc} */
-	public function display(){
-		if ($this->lastModified) {
-			header('Last-Modified: ' . gmdate('D, d M Y H:i:s ', $this->lastModified) . 'GMT');
-		}
-		echo $this->stringify();
-
-		return $this;
-	}
-
 	/**
 	 * {@inheritdoc}
 	 *
diff --git a/lib/FormatInterface.php b/lib/FormatInterface.php
index 82049d41..5fd46ef9 100644
--- a/lib/FormatInterface.php
+++ b/lib/FormatInterface.php
@@ -26,13 +26,6 @@ interface FormatInterface {
 	 */
 	public function stringify();
 
-	/**
-	 * Display the current data to the user
-	 *
-	 * @return self The format object
-	 */
-	public function display();
-
 	/**
 	 * Set items
 	 *
diff --git a/tests/AtomFormatTest.php b/tests/AtomFormatTest.php
index 91d6c1d8..1d692c40 100644
--- a/tests/AtomFormatTest.php
+++ b/tests/AtomFormatTest.php
@@ -14,21 +14,6 @@ class AtomFormatTest extends TestCase {
 	private $format;
 	private $data;
 
-	/**
-	 * @dataProvider sampleProvider
-	 * @runInSeparateProcess
-	 * @requires function xdebug_get_headers
-	 */
-	public function testHeaders($path) {
-		$this->setSample($path);
-		$this->initFormat();
-
-		$this->assertContains(
-			'Content-Type: application/atom+xml; charset=' . $this->format->getCharset(),
-			xdebug_get_headers()
-		);
-	}
-
 	/**
 	 * @dataProvider sampleProvider
 	 * @runInSeparateProcess
@@ -81,9 +66,7 @@ class AtomFormatTest extends TestCase {
 		$this->format->setExtraInfos($this->sample->meta);
 		$this->format->setLastModified(strtotime('2000-01-01 12:00:00 UTC'));
 
-		$_ = $this->format->display();
-		$this->data = $this->getActualOutput();
+		$this->data = $this->format->stringify();
 		$this->assertNotFalse(simplexml_load_string($this->data));
-		ob_clean();
 	}
 }
diff --git a/tests/JsonFormatTest.php b/tests/JsonFormatTest.php
index 9e19fe8f..9b536c18 100644
--- a/tests/JsonFormatTest.php
+++ b/tests/JsonFormatTest.php
@@ -15,21 +15,6 @@ class JsonFormatTest extends TestCase {
 	private $format;
 	private $data;
 
-	/**
-	 * @dataProvider sampleProvider
-	 * @runInSeparateProcess
-	 * @requires function xdebug_get_headers
-	 */
-	public function testHeaders($path) {
-		$this->setSample($path);
-		$this->initFormat();
-
-		$this->assertContains(
-			'Content-Type: application/json; charset=' . $this->format->getCharset(),
-			xdebug_get_headers()
-		);
-	}
-
 	/**
 	 * @dataProvider sampleProvider
 	 * @runInSeparateProcess
@@ -82,9 +67,7 @@ class JsonFormatTest extends TestCase {
 		$this->format->setExtraInfos($this->sample->meta);
 		$this->format->setLastModified(strtotime('2000-01-01 12:00:00 UTC'));
 
-		$_ = $this->format->display();
-		$this->data = $this->getActualOutput();
+		$this->data = $this->format->stringify();
 		$this->assertNotNull(json_decode($this->data), 'invalid JSON output: ' . json_last_error_msg());
-		ob_clean();
 	}
 }
diff --git a/tests/MrssFormatTest.php b/tests/MrssFormatTest.php
index 5ece3904..ed7dc3a3 100644
--- a/tests/MrssFormatTest.php
+++ b/tests/MrssFormatTest.php
@@ -15,21 +15,6 @@ class MrssFormatTest extends TestCase {
 	private $format;
 	private $data;
 
-	/**
-	 * @dataProvider sampleProvider
-	 * @runInSeparateProcess
-	 * @requires function xdebug_get_headers
-	 */
-	public function testHeaders($path) {
-		$this->setSample($path);
-		$this->initFormat();
-
-		$this->assertContains(
-			'Content-Type: application/rss+xml; charset=' . $this->format->getCharset(),
-			xdebug_get_headers()
-		);
-	}
-
 	/**
 	 * @dataProvider sampleProvider
 	 * @runInSeparateProcess
@@ -82,9 +67,7 @@ class MrssFormatTest extends TestCase {
 		$this->format->setExtraInfos($this->sample->meta);
 		$this->format->setLastModified(strtotime('2000-01-01 12:00:00 UTC'));
 
-		$_ = $this->format->display();
-		$this->data = $this->getActualOutput();
+		$this->data = $this->format->stringify();
 		$this->assertNotFalse(simplexml_load_string($this->data));
-		ob_clean();
 	}
 }