The Oznak were horsemen before they were a kingdom. When they first came down onto the western steppe, nothing on the open grass could stop a column of riders, and for the better part of two centuries nothing tried. The Ride is the name Ta Minn keeps for that long outward push. It was never one campaign. It was a habit of expansion handed down a generation at a time, each season's riders going to the edge of what their horses could cross and claiming the grass behind them, until the children of those riders went further still.
What stopped the Ride was not weather or distance. It was other people. Riding out in every direction, the Oznak eventually struck the edges of settled country on every side: the hill-built holds toward Thespia in the southwest, the broken stone of the Crags of Geth to the east where Griselia's goblins held the high ground, and the basin to the north. The present borders of Ta Minn are not lines anyone drew. They are the marks of where the open grass ran out and a neighbor was already dug in. The Kazigh of the day blessed the riders before each season and recalled fewer of them as the frontier hardened, and at some point within living memory the blessing changed from a send-off into a defense.
The northern frontier is the one that never settled. The basin there is Anarak, and Anarak is ruled by the black dragon Tepheranos, who built a poor country into a military state and has been hungry for room ever since. He cannot take that room where he wants it. A feud in the Kharvorn passes keeps his northern flank frozen against Argysis, and while that quarrel holds he cannot spend his army on the mountains. So the hunger turns south, onto the only open country within reach, which is Ta Minn's. The Kanüli Daha Plains are where it lands. A single river runs out of Anarak through the gap between the Kharvorn and Griselia ranges, and that gap is the one road an army can take onto the plains. Generations of Oznak have ridden north to hold it, and generations of Anarak's levies have come down it, and neither has ever owned the river for long.
Our grandfathers rode until the grass ended. Now we ride to where it ends and no further, and we call that the border, and a man comes down the river every spring to tell us it is his. — a saying of the Kanüli Daha outriders
The Ride is over in the sense that there is nowhere left to ride. It is not over in the sense that anyone has stopped fighting.