diff --git a/src/Hackspace/Bundle/CalciferBundle/libs/CalciferCaldavBackend.php b/src/Hackspace/Bundle/CalciferBundle/libs/CalciferCaldavBackend.php
new file mode 100644
index 0000000..cf5f95e
--- /dev/null
+++ b/src/Hackspace/Bundle/CalciferBundle/libs/CalciferCaldavBackend.php
@@ -0,0 +1,305 @@
+<?php
+/**
+ * Created by PhpStorm.
+ * User: tim
+ * Date: 15.11.14
+ * Time: 17:13
+ */
+
+namespace Hackspace\Bundle\CalciferBundle\libs;
+
+
+use Jsvrcek\ICS\CalendarStream;
+use Jsvrcek\ICS\Model\CalendarEvent;
+use Jsvrcek\ICS\Utility\Formatter;
+use Sabre\CalDAV\Backend\AbstractBackend;
+use Symfony\Bundle\FrameworkBundle\Controller\Controller;
+use Doctrine\ORM\EntityManager;
+use Doctrine\ORM\EntityRepository;
+use Doctrine\ORM\QueryBuilder;
+use Hackspace\Bundle\CalciferBundle\Entity\Event;
+
+class CalciferCaldavBackend extends AbstractBackend
+{
+    /** @var Controller */
+    private $controller = null;
+
+    function __construct(Controller $controller)
+    {
+        $this->controller = $controller;
+    }
+
+    /**
+     * Returns a list of calendars for a principal.
+     *
+     * Every project is an array with the following keys:
+     *  * id, a unique id that will be used by other functions to modify the
+     *    calendar. This can be the same as the uri or a database key.
+     *  * uri, which the basename of the uri with which the calendar is
+     *    accessed.
+     *  * principaluri. The owner of the calendar. Almost always the same as
+     *    principalUri passed to this method.
+     *
+     * Furthermore it can contain webdav properties in clark notation. A very
+     * common one is '{DAV:}displayname'.
+     *
+     * Many clients also require:
+     * {urn:ietf:params:xml:ns:caldav}supported-calendar-component-set
+     * For this property, you can just return an instance of
+     * Sabre\CalDAV\Property\SupportedCalendarComponentSet.
+     *
+     * @param string $principalUri
+     * @return array
+     */
+    public function getCalendarsForUser($principalUri)
+    {
+        return [[
+            'id' => 1,
+            'uri' => 'calendar',
+            'principaluri' => '/caldav/calcifer',
+        ]];
+    }
+
+    /**
+     * Creates a new calendar for a principal.
+     *
+     * If the creation was a success, an id must be returned that can be used to reference
+     * this calendar in other methods, such as updateCalendar.
+     *
+     * @param string $principalUri
+     * @param string $calendarUri
+     * @param array $properties
+     * @return void
+     */
+    public function createCalendar($principalUri, $calendarUri, array $properties)
+    {
+        throw new \Exception('Not implemented');
+    }
+
+    /**
+     * Delete a calendar and all it's objects
+     *
+     * @param mixed $calendarId
+     * @return void
+     */
+    public function deleteCalendar($calendarId)
+    {
+        throw new \Exception('Not implemented');
+    }
+
+    private function FormatCalendarEvent(CalendarEvent $event)
+    {
+        $stream = new CalendarStream();
+        $formatter = new Formatter();
+        $stream->addItem('BEGIN:VEVENT')
+            ->addItem('UID:' . $event->getUid())
+            ->addItem('DTSTART:' . $formatter->getFormattedUTCDateTime($event->getStart()))
+            ->addItem('DTEND:' . $formatter->getFormattedUTCDateTime($event->getEnd()))
+            ->addItem('SUMMARY:' . $event->getSummary())
+            ->addItem('DESCRIPTION:' . $event->getDescription());
+
+        if ($event->getClass())
+            $stream->addItem('CLASS:' . $event->getClass());
+
+        /* @var $location Location */
+        foreach ($event->getLocations() as $location) {
+            $stream
+                ->addItem('LOCATION' . $location->getUri() . $location->getLanguage() . ':' . $location->getName());
+        }
+
+        if ($event->getGeo())
+            $stream->addItem('GEO:' . $event->getGeo()->getLatitude() . ';' . $event->getGeo()->getLongitude());
+
+        if ($event->getUrl())
+            $stream->addItem('URL:' . $event->getUrl());
+
+        if ($event->getCreated())
+            $stream->addItem('CREATED:' . $formatter->getFormattedUTCDateTime($event->getCreated()));
+
+        if ($event->getLastModified())
+            $stream->addItem('LAST-MODIFIED:' . $formatter->getFormattedUTCDateTime($event->getLastModified()));
+
+        foreach ($event->getAttendees() as $attendee) {
+            $stream->addItem($attendee->__toString());
+        }
+
+        if ($event->getOrganizer())
+            $stream->addItem($event->getOrganizer()->__toString());
+
+        $stream->addItem('END:VEVENT');
+
+        return $stream->getStream();
+    }
+
+    private function formatEvent(Event $event)
+    {
+        /** @var CalendarEvent $calendar_event */
+        $calendar_event = $event->ConvertToCalendarEvent();
+        $calendar_data = $this->FormatCalendarEvent($calendar_event);
+
+        $event_data = [
+            'id' => $event->id,
+            'uri' => $event->slug,
+            'lastmodified' => $event->startdate,
+            'etag' => '"' . sha1($calendar_data) . '"',
+            'calendarid' => 1,
+            'calendardata' => $calendar_data,
+            'size' => strlen($calendar_data),
+            'component' => 'VEVENT',
+        ];
+        return $event_data;
+    }
+
+    /**
+     * Returns all calendar objects within a calendar.
+     *
+     * Every item contains an array with the following keys:
+     *   * id - unique identifier which will be used for subsequent updates
+     *   * calendardata - The iCalendar-compatible calendar data
+     *   * uri - a unique key which will be used to construct the uri. This can
+     *     be any arbitrary string, but making sure it ends with '.ics' is a
+     *     good idea. This is only the basename, or filename, not the full
+     *     path.
+     *   * lastmodified - a timestamp of the last modification time
+     *   * etag - An arbitrary string, surrounded by double-quotes. (e.g.:
+     *   '"abcdef"')
+     *   * calendarid - The calendarid as it was passed to this function.
+     *   * size - The size of the calendar objects, in bytes.
+     *   * component - optional, a string containing the type of object, such
+     *     as 'vevent' or 'vtodo'. If specified, this will be used to populate
+     *     the Content-Type header.
+     *
+     * Note that the etag is optional, but it's highly encouraged to return for
+     * speed reasons.
+     *
+     * The calendardata is also optional. If it's not returned
+     * 'getCalendarObject' will be called later, which *is* expected to return
+     * calendardata.
+     *
+     * If neither etag or size are specified, the calendardata will be
+     * used/fetched to determine these numbers. If both are specified the
+     * amount of times this is needed is reduced by a great degree.
+     *
+     * @param mixed $calendarId
+     * @return array
+     */
+    public function getCalendarObjects($calendarId)
+    {
+        /** @var EntityManager $em */
+        $em = $this->controller->getDoctrine()->getManager();
+
+        $now = new \DateTime();
+        $now->setTime(0, 0, 0);
+        /** @var QueryBuilder $qb */
+        $qb = $em->createQueryBuilder();
+        $qb->select(array('e'))
+            ->from('CalciferBundle:Event', 'e')
+            ->where('e.startdate >= :startdate')
+            ->orderBy('e.startdate')
+            ->setParameter('startdate', $now);
+        $entities = $qb->getQuery()->execute();
+
+        if (count($entities) > 0) {
+            $events = [];
+            foreach ($entities as $event) {
+                /** @var Event $event */
+                $events[] = $this->formatEvent($event);
+            }
+            return $events;
+        }
+    }
+
+    /**
+     * Returns information from a single calendar object, based on it's object
+     * uri.
+     *
+     * The object uri is only the basename, or filename and not a full path.
+     *
+     * The returned array must have the same keys as getCalendarObjects. The
+     * 'calendardata' object is required here though, while it's not required
+     * for getCalendarObjects.
+     *
+     * This method must return null if the object did not exist.
+     *
+     * @param mixed $calendarId
+     * @param string $objectUri
+     * @return array|null
+     */
+    public function getCalendarObject($calendarId, $objectUri)
+    {
+        /** @var EntityManager $em */
+        $em = $this->controller->getDoctrine()->getManager();
+
+        /** @var EntityRepository $repo */
+        $repo = $em->getRepository('CalciferBundle:Event');
+
+        /** @var Event $entity */
+        $event = $repo->findOneBy(['slug' => $objectUri]);
+
+        if (!($event instanceof Event)) {
+            throw $this->controller->createNotFoundException('Unable to find Event entity.');
+        }
+
+        return $this->formatEvent($event);
+    }
+
+    /**
+     * Creates a new calendar object.
+     *
+     * The object uri is only the basename, or filename and not a full path.
+     *
+     * It is possible return an etag from this function, which will be used in
+     * the response to this PUT request. Note that the ETag must be surrounded
+     * by double-quotes.
+     *
+     * However, you should only really return this ETag if you don't mangle the
+     * calendar-data. If the result of a subsequent GET to this object is not
+     * the exact same as this request body, you should omit the ETag.
+     *
+     * @param mixed $calendarId
+     * @param string $objectUri
+     * @param string $calendarData
+     * @return string|null
+     */
+    public function createCalendarObject($calendarId, $objectUri, $calendarData)
+    {
+        // TODO: Implement createCalendarObject() method.
+    }
+
+    /**
+     * Updates an existing calendarobject, based on it's uri.
+     *
+     * The object uri is only the basename, or filename and not a full path.
+     *
+     * It is possible return an etag from this function, which will be used in
+     * the response to this PUT request. Note that the ETag must be surrounded
+     * by double-quotes.
+     *
+     * However, you should only really return this ETag if you don't mangle the
+     * calendar-data. If the result of a subsequent GET to this object is not
+     * the exact same as this request body, you should omit the ETag.
+     *
+     * @param mixed $calendarId
+     * @param string $objectUri
+     * @param string $calendarData
+     * @return string|null
+     */
+    public function updateCalendarObject($calendarId, $objectUri, $calendarData)
+    {
+        throw new \Exception('Not implemented');
+    }
+
+    /**
+     * Deletes an existing calendar object.
+     *
+     * The object uri is only the basename, or filename and not a full path.
+     *
+     * @param mixed $calendarId
+     * @param string $objectUri
+     * @return void
+     */
+    public function deleteCalendarObject($calendarId, $objectUri)
+    {
+        throw new \Exception('Not implemented');
+    }
+}
\ No newline at end of file
diff --git a/src/Hackspace/Bundle/CalciferBundle/libs/CalciferPrincipalBackend.php b/src/Hackspace/Bundle/CalciferBundle/libs/CalciferPrincipalBackend.php
new file mode 100644
index 0000000..5ee84de
--- /dev/null
+++ b/src/Hackspace/Bundle/CalciferBundle/libs/CalciferPrincipalBackend.php
@@ -0,0 +1,158 @@
+<?php
+/**
+ * Created by PhpStorm.
+ * User: tim
+ * Date: 15.11.14
+ * Time: 19:45
+ */
+
+namespace Hackspace\Bundle\CalciferBundle\libs;
+
+use
+    Sabre\DAV,
+    Sabre\DAVACL,
+    Sabre\HTTP\URLUtil;
+
+class CalciferPrincipalBackend extends DAVACL\PrincipalBackend\AbstractBackend
+{
+
+    /**
+     * Returns a list of principals based on a prefix.
+     *
+     * This prefix will often contain something like 'principals'. You are only
+     * expected to return principals that are in this base path.
+     *
+     * You are expected to return at least a 'uri' for every user, you can
+     * return any additional properties if you wish so. Common properties are:
+     *   {DAV:}displayname
+     *   {http://sabredav.org/ns}email-address - This is a custom SabreDAV
+     *     field that's actually injected in a number of other properties. If
+     *     you have an email address, use this property.
+     *
+     * @param string $prefixPath
+     * @return array
+     */
+    function getPrincipalsByPrefix($prefixPath)
+    {
+        return [
+            [
+                '{DAV:}displayname' => 'calcifer',
+                '{http://sabredav.org/ns}email-address' => 'calcifer@example.com',
+                'uri' => '/caldav/calcifer',
+            ]
+        ];
+    }
+
+    /**
+     * Returns a specific principal, specified by it's path.
+     * The returned structure should be the exact same as from
+     * getPrincipalsByPrefix.
+     *
+     * @param string $path
+     * @return array
+     */
+    function getPrincipalByPath($path)
+    {
+        return [
+            '{DAV:}displayname' => 'calcifer',
+            '{http://sabredav.org/ns}email-address' => 'calcifer@example.com',
+            'uri' => '/caldav/calcifer',
+        ];
+    }
+
+    /**
+     * Updates one ore more webdav properties on a principal.
+     *
+     * The list of mutations is stored in a Sabre\DAV\PropPatch object.
+     * To do the actual updates, you must tell this object which properties
+     * you're going to process with the handle() method.
+     *
+     * Calling the handle method is like telling the PropPatch object "I
+     * promise I can handle updating this property".
+     *
+     * Read the PropPatch documenation for more info and examples.
+     *
+     * @param string $path
+     * @param \Sabre\DAV\PropPatch $propPatch
+     * @return void
+     */
+    function updatePrincipal($path, \Sabre\DAV\PropPatch $propPatch)
+    {
+        throw new \Exception('Not implemented');
+    }
+
+    /**
+     * This method is used to search for principals matching a set of
+     * properties.
+     *
+     * This search is specifically used by RFC3744's principal-property-search
+     * REPORT. You should at least allow searching on
+     * http://sabredav.org/ns}email-address.
+     *
+     * The actual search should be a unicode-non-case-sensitive search. The
+     * keys in searchProperties are the WebDAV property names, while the values
+     * are the property values to search on.
+     *
+     * If multiple properties are being searched on, the search should be
+     * AND'ed.
+     *
+     * This method should simply return an array with full principal uri's.
+     *
+     * If somebody attempted to search on a property the backend does not
+     * support, you should simply return 0 results.
+     *
+     * You can also just return 0 results if you choose to not support
+     * searching at all, but keep in mind that this may stop certain features
+     * from working.
+     *
+     * @param string $prefixPath
+     * @param array $searchProperties
+     * @return array
+     */
+    function searchPrincipals($prefixPath, array $searchProperties)
+    {
+        return [
+            [
+                '{DAV:}displayname' => 'calcifer',
+                '{http://sabredav.org/ns}email-address' => 'calcifer@example.com',
+                'uri' => '/caldav/calcifer',
+            ]
+        ];
+    }
+
+    /**
+     * Returns the list of members for a group-principal
+     *
+     * @param string $principal
+     * @return array
+     */
+    function getGroupMemberSet($principal)
+    {
+        throw new \Exception('Not implemented');
+    }
+
+    /**
+     * Returns the list of groups a principal is a member of
+     *
+     * @param string $principal
+     * @return array
+     */
+    function getGroupMembership($principal)
+    {
+        throw new \Exception('Not implemented');
+    }
+
+    /**
+     * Updates the list of group members for a group principal.
+     *
+     * The principals should be passed as a list of uri's.
+     *
+     * @param string $principal
+     * @param array $members
+     * @return void
+     */
+    function setGroupMemberSet($principal, array $members)
+    {
+        throw new \Exception('Not implemented');
+    }
+}
\ No newline at end of file