diff --git a/src/date_gui.h b/src/date_gui.h
new file mode 100644
--- /dev/null
+++ b/src/date_gui.h
@@ -0,0 +1,24 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file date_gui.h Functions related to the graphical selection of a date. */
+
+#ifndef DATE_GUI_H
+#define DATE_GUI_H
+
+/**
+ * Callback for when a date has been chosen
+ * @param w the window that sends the callback
+ * @param date the date that has been chosen
+ */
+typedef void SetDateCallback(const Window *w, Date date);
+
+void ShowSetDateWindow(Window *parent, int window_number, Date initial_date, Year min_year, Year max_year, SetDateCallback *callback);
+
+#endif /* DATE_GUI_H */