New kinds of graves, named after a grave at Suvorovo, appear about 4200-4000 BCE north of the Danube delta in the coastal steppes of Ukraine near Izmail, more than five hundred years before the geographic expansion evidenced by the presence of horse bones.

Suvorovo graves are similar to and probably derive from earlier funeral traditions in the steppes around the Dnieper River.

Some Suvorovo graves contain polished stone mace-heads shaped like horse heads and horse tooth beads.

Earlier steppe graves also had contained polished stone mace-heads, some of them carved in the shape of animal heads.

Settlements in the steppes contemporary with Suvorovo, such as Sredni Stog II and Dereivka on the Dnieper River, contained twelve to fifteen percent horse bones.

When Suvorovo graves appeared in the Danube delta grasslands, horse-head maces also appeared in some of the indigenous farming towns of the Tripolye and Gumelnitsa cultures in present-day Romania and Moldova, near the Suvorovo graves.

These agricultural cultures had not previously used polished-stone maces, and horse bones were rare or absent in their settlement sites.

Probably their horse-head maces had come from the Suvorovo immigrants.

The Suvorovo people in turn acquire many copper ornaments from the Tripolye and Gumelnitsa towns.

About six hundred agricultural towns in the Balkans and the lower Danube valley, some of which have been occupied for two thousand years, are abandoned after this episode of contact and trade, but still during the period 4200-4000 BCE.

Copper mining ceases in the Balkan copper mines, and the cultural traditions associated with the agricultural towns are terminated in the Balkans and the lower Danube valley.

This collapse of "Old Europe" has been attributed to the immigration of mounted Indo-European warriors, although the collapse could have been caused by intensified warfare, for which there is some evidence.

Mounted raiding could have worsened warfare; the horse-head maces have been interpreted as indicating the introduction of domesticated horses and riding just before the collapse.

However, mounted raiding is just one possible explanation for this complex event.

Also cited as causal factors are environmental deterioration, ecological degradation from millennia of farming, and the exhaustion of easily mined oxide copper ores.

Bone bits and horse remains in human graves found in the Eneolithic (fifth millennium) Samara culture at the middle Volga, a culture suggested as corresponding to the Proto-Indo-Europeans in the Kurgan hypothesis championed by twentieth century Lithuanian-American archeologist Marija Gimbutas, represent the earliest archaeological evidence of horse domestication.

It cannot yet be determined decisively if these horses were ridden or not, but they were certainly used as a meat-animal.

Recent discoveries concerning Botai culture suggest that Botai culture settlements in the Aqmola Province of Kazakhstan are the location of the earliest domestication of the horse.

However, an increasing amount of evidence supports the hypothesis that horses were domesticated in the Eurasian Steppe (Dereivka, centered in Ukraine) approximately 4000-3500 BCE.

The date of 4000 BCE is based on evidence that includes the appearance of dental pathologies associated with biting, changes in butchering practices, changes in human economies and settlement patterns, the depiction of horses as symbols of power in artifacts, and the appearance of horse bones in human graves.