It is now more common to accept that limes was not a term used by the Romans for the imperial frontier, fortified or not.

Of missions sent by Roman bishops beyond the imperial frontiers we hear nothing until the sixth century.

The imperial frontier had moved to the south, but pockets of unconquered territory remained in the rear.

We'll need to close the imperial frontier and turn them back before they get as far as Santa Rosa.

Limes was in fact not used to indicate the imperial frontier or a fortified border.

He had heard of glorious battles being waged on the imperial frontier, out toward the galactic rim.

In this connection Isaac has argued that the concept of an imperial frontier was irrelevant in Roman terms.

From that church came two missionaries who started to bring Christianity beyond the former imperial frontiers in Britain.

It seemed ages since I had been beyond imperial frontiers.

Yet events along the imperial frontier did not rest.