diff --git a/radicale/__init__.py b/radicale/__init__.py
index 6bbdc5a1..42d0936a 100644
--- a/radicale/__init__.py
+++ b/radicale/__init__.py
@@ -166,8 +166,8 @@ class Application(object):
             content = None
 
         # Find calendar(s)
-        items = ical.Calendar.from_path(environ["PATH_INFO"],
-            environ.get("HTTP_DEPTH", "0"))
+        items = ical.Calendar.from_path(
+            environ["PATH_INFO"], environ.get("HTTP_DEPTH", "0"))
 
         # Get function corresponding to method
         function = getattr(self, environ["REQUEST_METHOD"].lower())
diff --git a/radicale/ical.py b/radicale/ical.py
index c8c26563..393956d2 100644
--- a/radicale/ical.py
+++ b/radicale/ical.py
@@ -163,7 +163,12 @@ class Calendar(object):
     tag = "VCALENDAR"
 
     def __init__(self, path, principal=False):
-        """Initialize the calendar with ``cal`` and ``user`` parameters."""
+        """Initialize the calendar.
+
+        ``path`` must be the normalized relative path of the calendar, using
+        the slash as the folder delimiter, with no leading nor trailing slash.
+
+        """
         self.encoding = "utf-8"
         split_path = path.split("/")
         self.owner = split_path[0] if len(split_path) > 1 else None
@@ -193,9 +198,8 @@ class Calendar(object):
         result = []
 
         path = "/".join(attributes[:min(len(attributes), 2)])
-        path = path.replace("/", os.sep)
-        abs_path = os.path.join(FOLDER, path)
-        if os.path.isdir(abs_path) or len(attributes) == 1:
+        abs_path = os.path.join(FOLDER, path.replace("/", os.sep))
+        if os.path.isdir(abs_path):
             if depth == "0":
                 result.append(cls(path, principal=True))
             else:
@@ -203,11 +207,10 @@ class Calendar(object):
                     result.append(cls(path, principal=True))
                 try:
                     for filename in next(os.walk(abs_path))[2]:
-                        file_path = os.path.join(path, filename)
                         if cls.is_vcalendar(os.path.join(abs_path, filename)):
-                            result.append(cls(file_path))
+                            result.append(cls(os.path.join(path, filename)))
                 except StopIteration:
-                    # directory does not exist yet
+                    # Directory does not exist yet
                     pass
         else:
             calendar = cls(path)
@@ -298,8 +301,6 @@ class Calendar(object):
 
     def write(self, headers=None, items=None):
         """Write calendar with given parameters."""
-        if self.is_principal:
-            return
         headers = headers or self.headers or (
             Header("PRODID:-//Radicale//NONSGML Radicale Server//EN"),
             Header("VERSION:2.0"))
@@ -415,11 +416,11 @@ class Calendar(object):
     def owner_url(self):
         """Get the calendar URL according to its owner."""
         if self.owner:
-            return ('/%s/' % self.owner).replace('//', '/')
+            return "/%s/" % self.owner
         else:
             return None
 
     @property
     def url(self):
         """Get the standard calendar URL."""
-        return ('/%s/' % self.local_path).replace('//', '/')
+        return "/%s/" % self.local_path
diff --git a/radicale/xmlutils.py b/radicale/xmlutils.py
index 37f6f806..b5d28bca 100644
--- a/radicale/xmlutils.py
+++ b/radicale/xmlutils.py
@@ -201,7 +201,7 @@ def _propfind_response(path, item, props, user):
     response = ET.Element(_tag("D", "response"))
 
     href = ET.Element(_tag("D", "href"))
-    href.text = item.url if is_calendar else "%s/%s" % (path, item.name)
+    href.text = item.local_path if is_calendar else "%s/%s" % (path, item.name)
     response.append(href)
 
     propstat404 = ET.Element(_tag("D", "propstat"))
@@ -264,9 +264,11 @@ def _propfind_response(path, item, props, user):
             if tag == _tag("D", "getcontenttype"):
                 element.text = "text/calendar"
             elif tag == _tag("D", "resourcetype"):
-                if not item.is_principal:
-                    tag = ET.Element(_tag("C", "calendar"))
+                if item.is_principal:
+                    tag = ET.Element(_tag("D", "principal"))
                     element.append(tag)
+                tag = ET.Element(_tag("C", "calendar"))
+                element.append(tag)
                 tag = ET.Element(_tag("D", "collection"))
                 element.append(tag)
             elif tag == _tag("D", "owner") and item.owner_url:
@@ -284,6 +286,9 @@ def _propfind_response(path, item, props, user):
         # Not for calendars
         elif tag == _tag("D", "getcontenttype"):
             element.text = "text/calendar; component=%s" % item.tag.lower()
+        elif tag == _tag("D", "resourcetype"):
+            # resourcetype must be returned empty for non-collection elements
+            pass
         else:
             is404 = True