diff --git a/pelican/__init__.py b/pelican/__init__.py
index 8de68d69..dcdbdcb6 100644
--- a/pelican/__init__.py
+++ b/pelican/__init__.py
@@ -6,7 +6,7 @@ import time
 
 from pelican.generators import (ArticlesGenerator, PagesGenerator,
         StaticGenerator, PdfGenerator)
-from pelican.settings import read_settings
+from pelican.settings import read_settings, _DEFAULT_CONFIG
 from pelican.utils import clean_output_dir, files_changed
 from pelican.writers import Writer
 from pelican import log
@@ -20,6 +20,9 @@ class Pelican(object):
         """Read the settings, and performs some checks on the environment
         before doing anything else.
         """
+        if settings is None:
+            settings = _DEFAULT_CONFIG
+
         self.path = path or settings['PATH']
         if not self.path:
             raise Exception('you need to specify a path containing the content'
@@ -28,44 +31,11 @@ class Pelican(object):
         if self.path.endswith('/'):
             self.path = self.path[:-1]
 
-        if settings.get('CLEAN_URLS', False):
-            log.warning('Found deprecated `CLEAN_URLS` in settings. Modifing'
-                        ' the following settings for the same behaviour.')
-
-            settings['ARTICLE_URL'] = '{slug}/'
-            settings['ARTICLE_LANG_URL'] = '{slug}-{lang}/'
-            settings['PAGE_URL'] = 'pages/{slug}/'
-            settings['PAGE_LANG_URL'] = 'pages/{slug}-{lang}/'
-
-            for setting in ('ARTICLE_URL', 'ARTICLE_LANG_URL', 'PAGE_URL',
-                            'PAGE_LANG_URL'):
-                log.warning("%s = '%s'" % (setting, settings[setting]))
-
-        if settings.get('ARTICLE_PERMALINK_STRUCTURE', False):
-            log.warning('Found deprecated `ARTICLE_PERMALINK_STRUCTURE` in'
-                        ' settings.  Modifing the following settings for'
-                        ' the same behaviour.')
-
-            structure = settings['ARTICLE_PERMALINK_STRUCTURE']
-
-            # Convert %(variable) into {variable}.
-            structure = re.sub('%\((\w+)\)s', '{\g<1>}', structure)
-
-            # Convert %x into {date:%x} for strftime
-            structure = re.sub('(%[A-z])', '{date:\g<1>}', structure)
-
-            # Strip a / prefix
-            structure = re.sub('^/', '', structure)
-
-            for setting in ('ARTICLE_URL', 'ARTICLE_LANG_URL', 'PAGE_URL',
-                            'PAGE_LANG_URL', 'ARTICLE_SAVE_AS',
-                            'ARTICLE_LANG_SAVE_AS', 'PAGE_SAVE_AS',
-                            'PAGE_LANG_SAVE_AS'):
-                settings[setting] = os.path.join(structure, settings[setting])
-                log.warning("%s = '%s'" % (setting, settings[setting]))
-
         # define the default settings
         self.settings = settings
+
+        self._handle_deprecation()
+
         self.theme = theme or settings['THEME']
         output_path = output_path or settings['OUTPUT_PATH']
         self.output_path = os.path.realpath(output_path)
@@ -82,6 +52,45 @@ class Pelican(object):
             else:
                 raise Exception("Impossible to find the theme %s" % theme)
 
+    def _handle_deprecation(self):
+
+        if self.settings.get('CLEAN_URLS', False):
+            log.warning('Found deprecated `CLEAN_URLS` in settings. Modifing'
+                        ' the following settings for the same behaviour.')
+
+            self.settings['ARTICLE_URL'] = '{slug}/'
+            self.settings['ARTICLE_LANG_URL'] = '{slug}-{lang}/'
+            self.settings['PAGE_URL'] = 'pages/{slug}/'
+            self.settings['PAGE_LANG_URL'] = 'pages/{slug}-{lang}/'
+
+            for setting in ('ARTICLE_URL', 'ARTICLE_LANG_URL', 'PAGE_URL',
+                            'PAGE_LANG_URL'):
+                log.warning("%s = '%s'" % (setting, self.settings[setting]))
+
+        if self.settings.get('ARTICLE_PERMALINK_STRUCTURE', False):
+            log.warning('Found deprecated `ARTICLE_PERMALINK_STRUCTURE` in'
+                        ' settings.  Modifing the following settings for'
+                        ' the same behaviour.')
+
+            structure = self.settings['ARTICLE_PERMALINK_STRUCTURE']
+
+            # Convert %(variable) into {variable}.
+            structure = re.sub('%\((\w+)\)s', '{\g<1>}', structure)
+
+            # Convert %x into {date:%x} for strftime
+            structure = re.sub('(%[A-z])', '{date:\g<1>}', structure)
+
+            # Strip a / prefix
+            structure = re.sub('^/', '', structure)
+
+            for setting in ('ARTICLE_URL', 'ARTICLE_LANG_URL', 'PAGE_URL',
+                            'PAGE_LANG_URL', 'ARTICLE_SAVE_AS',
+                            'ARTICLE_LANG_SAVE_AS', 'PAGE_SAVE_AS',
+                            'PAGE_LANG_SAVE_AS'):
+                self.settings[setting] = os.path.join(structure,
+                                                      self.settings[setting])
+                log.warning("%s = '%s'" % (setting, self.settings[setting]))
+
     def run(self):
         """Run the generators and return"""
 
diff --git a/pelican/settings.py b/pelican/settings.py
index d62acf42..bfc8e940 100644
--- a/pelican/settings.py
+++ b/pelican/settings.py
@@ -61,7 +61,7 @@ _DEFAULT_CONFIG = {'PATH': None,
                    }
 
 
-def read_settings(filename):
+def read_settings(filename=None):
     """Load a Python file into a dictionary.
     """
     context = _DEFAULT_CONFIG.copy()