Around the gentle, rounded Cheviot hills, evidence of once thriving, self-sustaining settlements punctuate the landscape. Steep terraces for growing crops contour the hillsides. Ridges and furrows from ploughing are etched into valleys. Large, circular mounds provide evidence of hill forts alongside outlines of timber roundhouses in faint circles. In these magnificent uplands, amid the tumbling lapwings and ascending skylarks, agriculture survived and prospered, albeit in a near-Mediterranean climate.

In a small museum near the 11th-century St Michael's church in the village of Ingram, vivid displays of another life give a sense of the effort involved in preparing the land for relatively sophisticated farming and creating the capacity for storing food for hundreds of people, maybe more.

So rich is the archaeological treasure trove in this part of the Northumberland National Park – the fertile valley of the River Breamish and the varied uplands rich in prehistory, amid later signs of Roman occupation – that five Iron Age hill forts, collectively one of the country's largest ancient monuments, are linked in a spectacular 4.5-mile upland trail. It is a testament to the earliest agriculture.

With polished axes, aspiring farmers created patches large enough to sow cereals such as wheat, oats and barley. Domestic animals, maybe sheep, cattle and pigs, were probably introduced from the Bronze Age and into the Iron Age, roaming the uplands in a setting doubtless beloved by some of today's re-wilding enthusiasts – more on them later – until the Romans subsequently cleared the remaining woodlands. “But we are reaching back to a time when there was no record,” laments Chris Jones, the National Park's archaeologist. “How did they farm and for how many? What were they able to grow? We can speculate; to what extent was this subsistence farming, cooperative living, or the development of markets – a capitalist approach if you like?” Although much has been discovered in several archaeological excavations, countless acres remain untouched in this multicoloured landscape as spring submits to summer, a rich palette of green laced with bracken, rust-tinged undergrowth blending with purpling heather and silver, rocky outcrops.