diff --git a/layout-per-window.py b/layout-per-window.py
index b5c679e..e4ce903 100755
--- a/layout-per-window.py
+++ b/layout-per-window.py
@@ -1,34 +1,50 @@
 #!/usr/bin/env python
 
 # This script keeps track of the active layout for each window.
+# Optional argument defines numeric layout index for new windows (counted from 0)
 #
 # This script requires i3ipc-python package (install it from a system package
 # manager or pip).
 
+import sys
+from typing import Optional
+
 import i3ipc
 
 
 def on_window_focus(ipc: i3ipc.connection.Connection, event: i3ipc.events.WindowEvent):
-    global windows, prev_focused
+    global windows, prev_focused, default_layout
+
+    # Get current layouts
+    layouts = {
+        input.identifier: input.xkb_active_layout_index for input in ipc.get_inputs()
+    }
 
-    # Save current layout
-    layouts = {input.identifier : input.xkb_active_layout_index
-               for input in ipc.get_inputs()}
+    # Save layouts for previous window
     windows[prev_focused] = layouts
 
-    # Restore layout of the newly focused window
+    # Restore layout of the newly focused known window
     if event.container.id in windows:
-        for (kdb_id, layout_index) in windows[event.container.id].items():
+        for kdb_id, layout_index in windows[event.container.id].items():
             if layout_index != layouts[kdb_id]:
                 ipc.command(f'input "{kdb_id}" xkb_switch_layout {layout_index}')
                 break
 
+    # Set default layout for a fresh window
+    elif default_layout is not None:
+        for kdb_id, layout_index in layouts.items():
+            if layout_index is not None and layout_index != default_layout:
+                ipc.command(f'input "{kdb_id}" xkb_switch_layout {default_layout}')
+                break
+
     prev_focused = event.container.id
 
+
 def on_window_close(ipc: i3ipc.connection.Connection, event: i3ipc.events.WindowEvent):
     global windows
     if event.container.id in windows:
-        del(windows[event.container.id])
+        del windows[event.container.id]
+
 
 def on_window(ipc: i3ipc.connection.Connection, event: i3ipc.events.WindowEvent):
     if event.change == "focus":
@@ -36,14 +52,26 @@ def on_window(ipc: i3ipc.connection.Connection, event: i3ipc.events.WindowEvent)
     elif event.change == "close":
         on_window_close(ipc, event)
 
+
 if __name__ == "__main__":
+    default_layout: Optional[int] = None
+    if len(sys.argv) == 2:
+        if sys.argv[1].isnumeric():
+            default_layout = int(sys.argv[1])
+        else:
+            print(f"Expected an integer, got: {sys.argv[1]}", file=sys.stderr)
+            sys.exit(2)
+    elif len(sys.argv) > 2:
+        print("Too many arguments", file=sys.stderr)
+        sys.exit(2)
+
     ipc = i3ipc.Connection()
     focused = ipc.get_tree().find_focused()
     if focused:
         prev_focused = focused.id
     else:
         prev_focused = None
-    windows = {} # type: dict
+    windows: dict = {}
 
     ipc.on("window", on_window)
     ipc.main()