Above the Wachau, in the forested hills on the south bank, a watchtower stood in the Roman period, and its stones are a quiet reminder that this valley was once the border of an empire. The Danube was the northern frontier of the province of Noricum, and the Romans guarded it with forts and signal towers every few kilometres, a chain that now forms part of the UNESCO listing for the Danube Limes. The tower near St Johann im Mauerthale was one of these, placed to see along the river and warn of anyone crossing from the north. Not much remains but the foundations, and they sit in a place with a long view.
St Johann im Mauerthale is a tiny hamlet with a small church in the hills above the village of Aggsbach, in a landscape of woods and clearings. Aggsbach itself has the ruins of a Carthusian monastery, and above it stands the castle of Aggstein, a ruin on a rock spur high over the Danube. Its most famous owner, a medieval robber baron of the Kuenringer family, is said to have imprisoned captives on a tiny rock ledge, called the Rosengartlein, the little rose garden, to extort ransom, and let them starve if they refused to pay. Whatever the truth, the castle is a dramatic sight and a good walk.
The riding in these hills is quieter than along the river, with narrow, winding lanes through woods, orchards and farms. The surfaces are mostly good, though a few are patched or gravelly, and the gradients can be steep. Weather in the hills is changeable, and the fog in autumn can be thick. The lane from Spitz up to the plateau and the Jauerling, the highest point of the area at 960 metres, is a pleasure, with long views and a sense of space. Traffic is light, and the farm shops sell apricot jam and schnapps.
Spitz, three kilometres away, has a few shops and cafes, and Krems is the nearest place to be sure of fuel. Look for a farm stall selling honey and cheese, and try the apricot cake in a village inn. In late summer, the plums are ripe, and in autumn, the walnut harvest begins, and the smell of wood smoke fills the air.