Why is my rich:calendar not working?

I want to show a rich:calendar on my xhtml site. Here is my code. I don't understand why its not working (that code doesn't show a calendar). I don't get any errors, the calendar isn't appearing.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:rich="http://richfaces.org/rich"
>

<f:view>
    <h:head>
        <title>Title</title>
    </h:head>
    <h:body>
        <h:panelGrid columns="2" styleClass="center">
            <h:outputText value="Date from" />
            <rich:calendar id="calendar_from" datePattern="d/M/yy HH:mm" value="18/11/12 09:00" popup="true" locale="de/DE" />
        </h:panelGrid>
    </h:body>
</f:view>
</html>

Solution

Make sure that the richfaces jar in classpath...