diff --git a/jabber-chat.el b/jabber-chat.el
index 9f3ec0c..a71328d 100644
--- a/jabber-chat.el
+++ b/jabber-chat.el
@@ -278,10 +278,11 @@ This function is idempotent."
 	     (cons "Display more context" 'jabber-chat-display-more-backlog))
 
 (defun jabber-chat-display-more-backlog (how-many)
-  (interactive "nHow many more messages? ")
+  "Display more context. HOW-MANY is number of messages. Specify 0 to display all messages."
+  (interactive "nHow many more messages (Specify 0 to display all)? ")
   (let* ((inhibit-read-only t)
 	 (jabber-backlog-days nil)
-	 (jabber-backlog-number how-many)
+	 (jabber-backlog-number (if (= how-many 0) t how-many))
 	 (backlog-entries (jabber-history-backlog
 			   jabber-chatting-with jabber-chat-earliest-backlog)))
     (when backlog-entries
diff --git a/jabber-history.el b/jabber-history.el
index 3544be7..e64f9c4 100644
--- a/jabber-history.el
+++ b/jabber-history.el
@@ -207,8 +207,9 @@ of the log file."
                 (let ((file (pop matched-files)))
                   (progn
                     (insert-file-contents file)
-                    (if (>= (count-lines (point-min) (point-max)) number)
-                        (setq lines-collected t)))))))))
+                    (when (numberp number)
+                      (if (>= (count-lines (point-min) (point-max)) number)
+                        (setq lines-collected t))))))))))
       (let (collected current-line)
 	(goto-char (point-max))
 	(catch 'beginning-of-file