Some time ago I visited some Italian cities from Germany by train. I could have done that tour with little changes 2000 years earlier. Of course I would have to get over the Limes first to enter the civilized parts of Germany in Mogontiacum. Augusta Raurica is not far off present day Basel where I spent a day. The Swiss train through the Brenner base tunnel was certainly preferable to a mule trek across dangerous mountain passes. But al the cities were there, Mediolanum, Florentia, and Roma.