diff --git a/src/Engine.php b/src/Engine.php
index e5a8889..b2c8255 100644
--- a/src/Engine.php
+++ b/src/Engine.php
@@ -68,6 +68,9 @@ class Engine
     {
         $this->articles = new \ArrayIterator();
         $this->xml = simplexml_load_string($string);
+        $this->activeArticle = false;
+        $this->calcVariables = [];
+        $this->variables = [];
         $this->parse();
         return true;
     }