The very first tag was (and still is) <;em>;, which is short code for </;em>emphasis.

In an attempt to make web formatting easier in HTML 2 (around 1993), the W3Calso allowed the more obvious <;i>; tag, which stands for </;i>italic. But this decision was against their very own principle of not letting HTML tags define physical formatting or any visual appearance. Tags should describe a semantic aspect.

So with recent versions of HTML (4 and 5) the W3C decided to roll back to that old principle and reinstate the <;i>; as the sole tag for </;i>emphasis, which will very likely render as italics on screens and in print. (And speech interfaces can interpret it in their own ways, like varying the pronunciation.)

Nevertheless, most screen browsers are forgiving, and do render both tags as italics, unless you're using the super strict version of XHTML !

BTW: the exact thing happened with the tags for bold: <;strong>; versus <;b>;.</;b></;strong>

Oorspronkelijk geplaatst op Quora: How do I do italics in HTML?"