In such an era where everything relies on manpower, completing communication work is a very difficult task.
Their only way to deliver messages is to urge the fastest horse to run the farthest road.
As for things like sending messages via carrier pigeon, they have not yet appeared, nor is there any disposition related to pigeons for this purpose.
Or perhaps, although pigeons do exist at this moment, no one has thought to associate them with message delivery.
Precisely because of this, even if someone really discovers the situation here and wants to send a message out, it takes several days,
and this delay of several days is enough to complete certain tasks.
This is also the reason for the classic saying, "in the field, military orders may not be observed."
This saying really only applies to ancient times like now; applying it to the modern world or the 21st century makes it completely useless.
