Spring 3.0 – Unable to locate Spring NamespaceHandler for XML schema namespace [http://www.springframework.org/schema/security]

I needed to add an additional Maven dependency:

    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-config</artifactId>
        <version>3.0.1.RELEASE</version>
    </dependency>