Backbone Router – Browser Back Button Not Triggering Router Methods

I have a Backbone Router set up that seemingly works – the routes get triggered properly, the views update, etc. However, when I press the browser's "Back" button, the routes aren't triggered at all. Also, typing in a URL into the browser doesn't trigger the routers either. Is there some step I'm missing to bind the browser specific things to Backbone (Firefox 11).

Setup

var messageRouter = new MessageRouter({view: messageListView});
Backbone.history.start();

Trigger

Backbone.history.navigate("#/view/" + $(this).data("filter-type"), {trigger: true});

Router Code

var MessageRouter = Backbone.Router.extend({

    view : null, /* should always be overridden */

    initialize : function(options)
    {
        this.view = options.view;
    },

    routes : {
        "" : "default",
        "/view/:filter" : "filter",
        "camera" : "camera"
    },

    default : function() {
    },

    filter : function(filterString) {
        this.view.setFilter(filterString);
        this.view.rerender();
    },

    camera : function(cameraString) {
    }

});