Please allow me to recommend this... http://orbis.stanford.edu/via/

In addation to the awesome map /u/PaulAJK has, [this] (http://www.ancient.eu/map_pelagios/) map is zoomable. If you don't want ads for it, use [this one which is the same.] (http://pelagios.org/maps/greco-roman/)

[This one also has a key.] (http://i.imgur.com/lHoCQtt.jpg)

This map is zoomable, panable, and generally quick and easy to use. You can also click on towns to see what we know about them, including roughly when they were founded.