diff --git a/formats/bold.js b/formats/bold.js
index cdabfb2372..a507ad5f22 100644
--- a/formats/bold.js
+++ b/formats/bold.js
@@ -1,7 +1,22 @@
 import Inline from '../blots/inline';
 
-class Bold extends Inline { }
+class Bold extends Inline {
+  static create(value) {
+    return super.create();
+  }
+
+  static formats(domNode) {
+    return true;
+  }
+
+  optimize() {
+    super.optimize();
+    if (this.domNode.tagName !== this.statics.tagName[0]) {
+      this.replaceWith(this.statics.blotName);
+    }
+  }
+}
 Bold.blotName = 'bold';
-Bold.tagName = 'STRONG';
+Bold.tagName = ['STRONG', 'B'];
 
 export default Bold;
diff --git a/formats/italic.js b/formats/italic.js
index b3ad324471..6d50f39f53 100644
--- a/formats/italic.js
+++ b/formats/italic.js
@@ -1,7 +1,7 @@
-import Inline from '../blots/inline';
+import Bold from './bold';
 
-class Italic extends Inline { }
+class Italic extends Bold { }
 Italic.blotName = 'italic';
-Italic.tagName = 'EM';
+Italic.tagName = ['EM', 'I'];
 
 export default Italic;
diff --git a/test/unit.js b/test/unit.js
index f0f21873c7..6a0e12eabf 100644
--- a/test/unit.js
+++ b/test/unit.js
@@ -19,6 +19,7 @@ import './unit/formats/code';
 import './unit/formats/header';
 import './unit/formats/indent';
 import './unit/formats/list';
+import './unit/formats/bold';
 
 import './unit/modules/clipboard';
 import './unit/modules/history';
diff --git a/test/unit/formats/bold.js b/test/unit/formats/bold.js
new file mode 100644
index 0000000000..1f08d39594
--- /dev/null
+++ b/test/unit/formats/bold.js
@@ -0,0 +1,13 @@
+import Scroll from '../../../blots/scroll';
+
+
+describe('Bold', function() {
+  it('optimize and merge', function() {
+    let scroll = this.initialize(Scroll, '<p><strong>a</strong>b<strong>c</strong></p>');
+    let bold = document.createElement('b');
+    bold.appendChild(scroll.domNode.firstChild.childNodes[1]);
+    scroll.domNode.firstChild.insertBefore(bold, scroll.domNode.firstChild.lastChild);
+    scroll.update();
+    expect(scroll.domNode).toEqualHTML('<p><strong>abc</strong></p>');
+  });
+});