dumb <ul> question

I said 'dumb' because I feel like I should know this with all the experience I've had with HTML5... i'm probably just missing something really stupid... but here's the code, I've having trouble centering the <ul>:

CSS:
#nav {background-color: #804000; float: left; padding: 5px; margin:2px;}

HTML:
<ul style="list-style:none;" align="center">
<li id="nav" onclick="hide('ma')">MIDDLE AGES</li>
<li id="nav" onclick="hide('rn')">RENNAISSANCE</li>
<li id="nav" onclick="hide('bb')">BAROQUE</li>
<li id="nav" onclick="hide('cc')">CLASSICAL</li>
<li id="nav" onclick="hide('rr')">ROMANTIC</li>
<li id="nav" onclick="hide('me')">MODERN EUROPE</li>
<li id="nav" onclick="hide('mna')">MODERN NORTH AMERICA</li></ul>

I've also tried other things, like <center>, style="text-align: center;" and more

what I do is center with margins in css. Likewise

#container {
margin-left:auto;
margin-right:auto;
width:9999999999999999999px;
}

#nav {
//style stuff here
}

.. Then do this:

<div id="container"><div id="nav">ul stuff here </div></div>

The code in your first message doesn't match the code in your second message, so it's hard to know which version you want fixed. It's also difficult to understand what you want centered: is it the<ul> list as a block, or do you just want to center the text contained in the individual <li> elements?