<table border="1">
<thead>
<tr>
<th colspan="2" rowspan="2">
This header spans two columns and two rows
</th>
<th>Header A</th>
</tr>
<tr>
<th>Header B</th>
</tr>
</thead>
<tbody>
<tr>
<td>Cell A</td>
<td>Cell B</td>
<td>Cell C</td>
</tr>
</tbody>
</table>