diff --git a/frank/frank.py b/frank/frank.py
index 516e509..90fbe6f 100644
--- a/frank/frank.py
+++ b/frank/frank.py
@@ -23,20 +23,21 @@ class Frank(discord.Client):
     their own behavior.
     """
 
-    PREFIX = 'fr'
-    """Prefix to use Frank inside Discord."""
-
-    def __init__(self, modules: List[Module], config_file: str = 'frank.yaml'):
+    def __init__(self, modules: List[Module], config_file: str = 'frank.yaml',
+                 prefix: str = 'fr'):
         """
         Args:
             modules: modules to load
             config_file: path to yaml config file; ignored if non-existent
+            prefix: prefix to activate Frank in the Discord server
         """
 
         super().__init__()
         self._modules = modules
         self._loaded_modules = []
 
+        self.PREFIX = prefix
+
         try:
             with open(config_file, 'r') as f:
                 self._config = yaml.load(f, Loader=yaml.FullLoader)