diff --git a/core/modules/widgets/element.js b/core/modules/widgets/element.js
index b3a970959..8253b70e1 100755
--- a/core/modules/widgets/element.js
+++ b/core/modules/widgets/element.js
@@ -25,7 +25,6 @@ Render this widget into the DOM
 */
 ElementWidget.prototype.render = function(parent,nextSibling) {
 	this.parentDomNode = parent;
-	this.computeAttributes();
 	// Neuter blacklisted elements
 	this.tag = this.parseTreeNode.tag;
 	if($tw.config.htmlUnsafeElements.indexOf(this.tag) !== -1) {
@@ -42,15 +41,8 @@ ElementWidget.prototype.render = function(parent,nextSibling) {
 		headingLevel = Math.min(Math.max(headingLevel + 1 + baseLevel,1),6);
 		this.tag = "h" + headingLevel;
 	}
-	// Check for element mapping
-	var mappedTag = this.getVariable("tv-map-" + this.tag);
-	if(mappedTag) {
-		this.tag = mappedTag.trim();
-		var mappedClass = this.getVariable("tv-map-" + this.tag + "-class");
-		if(mappedClass) {
-			this.setAttribute("class",mappedClass.trim() + (this.getAttribute("class") ? " " + this.getAttribute("class") : ""));
-		}
-	}
+	// Compute the attributes, mapping the element tag if needed
+	this.computeAttributes();
 	// Select the namespace for the tag
 	var XHTML_NAMESPACE = "http://www.w3.org/1999/xhtml",
 		tagNamespaces = {
@@ -108,4 +100,25 @@ ElementWidget.prototype.refresh = function(changedTiddlers) {
 	return this.refreshChildren(changedTiddlers) || hasChangedAttributes;
 };
 
+/*
+Override the base computeAttributes method
+*/
+ElementWidget.prototype.computeAttributes = function() {
+	// Call the base class to compute the initial values of the attributes
+	var changedAttributes = Widget.prototype.computeAttributes.call(this);
+	// Check for element mapping
+	var mappedTag = this.getVariable("tv-map-" + this.tag),
+		mappedClass = this.getVariable("tv-map-" + this.tag + "-class");
+	if(mappedTag) {
+		this.tag = mappedTag.trim();
+		// Add an attribute to indicate the original tag
+		this.attributes["data-element-mapping-from"] = this.parseTreeNode.tag;
+		// Check for a mapped class
+		if(mappedClass) {
+			this.attributes["class"] = mappedClass.trim() + (this.attributes["class"] ? " " + this.attributes["class"] : "");
+		}
+	}
+	return changedAttributes;
+};
+
 exports.element = ElementWidget;
diff --git a/editions/test/tiddlers/tests/data/element-mapping/Basic.tid b/editions/test/tiddlers/tests/data/element-mapping/Basic.tid
index 008e0204a..2b5298ce8 100644
--- a/editions/test/tiddlers/tests/data/element-mapping/Basic.tid
+++ b/editions/test/tiddlers/tests/data/element-mapping/Basic.tid
@@ -16,4 +16,4 @@ This is a paragraph
 +
 title: ExpectedResult
 
-<div class="my-class">This is a paragraph</div>
\ No newline at end of file
+<div class="my-class" data-element-mapping-from="p">This is a paragraph</div>
\ No newline at end of file