In a pre-mechanical and pre-electronic world, communication was by land and sea couriers.
It therefore established river and sea transport for those cities near water, and for the others, post-houses which held relays of horses for couriers to use carrying messages.
Of course these transportation routes also carried commercial and military traffic.
A system of sea, river and road transport.
A fleet, and internal roads with posting houses for horsed couriers.
Ships around the coast and in the rivers, seas and lakes, and a horse-relay courier system by land.
A fleet of ships was the most efficient. For those areas not accessible by water, there was a horsed courier system with way stations with fresh mounts to speed progress.
Firstly their ships through the Mediterranean Sea, the Black Sea, the Persian Gulf and the rivers flowing into them. Inland, by roads, with posting-houses where couriers changed horses, to deliver messages.
It established sea and river communications, and a road system for internal couriers and traffic.
A system of sea, river and road transport.
Ships in the coastal areas, and courier tracks in the inland areas.
A fleet, and internal roads with posting houses for horsed couriers.
There were two means - coastal ships and a post-horse courier system in land areas.
A track for mounted couriers with remount stations provided fast movement in areas with no water transport.
Sea transport and a system of tracks with way stations for mounted couriers.
It's systematic use of sea and river craft and posting road horse couriers.
Ships around the coast and in the rivers, seas and lakes, and a horse-relay courier system by land.
Persian empire
A fleet of ships was the most efficient. For those areas not accessible by water, there was a horsed courier system with way stations with fresh mounts to speed progress.
Firstly their ships through the Mediterranean Sea, the Black Sea, the Persian Gulf and the rivers flowing into them. Inland, by roads, with posting-houses where couriers changed horses, to deliver messages.