First, there are several PODs for this TL - they will all be revealed in time. Second, this won't be pure Romanwank - Rome will face difficulties and challenges as much as any other power.
AVE IMPERATOR! - A Roman Printing Press and Industrial Revolution
99 AD
The carver works in the blistering summer heat, painstakingly carving words into a stone plaque that will be used in a fountain. Then something happens, one of those little accidents that change the course of history forever. A plumber, working nearby, accidentally spills molten lead onto the plaque, the carver backing away in fright. The other people working on the fountain lift the hardened lead off the stone and lay it down on the sand. They wait for it to cool down and then lift it off, seeing the half-completed but clearly legible inscription on the sand.
Suddenly, the carver experiences a flash of insight, of pure inspiration. He cuts the lead into letters and prints images in the sand. A group of Senators happen to walk by, at first wondering what is happening then coming closer and realising the sheer importance of this to communication. A conversation ensues, and they take the pieces of lead, ready to take them to Caesar, demonstrate their importance.
Far away, a boy called Caelius Marius Valerian is growing into adulthood. His ideas will be more important to Rome than even he knows...