The Tarpan was a wild horse of Eastern and Southeastern Europe. Most likely it was grulla in color, although according to some sources some may have been dun-colored as well. While some zoologists considered the Tarpan the ancestor of all domestic horse breeds, others claimed the Tarpan to have been not a real wild horse, but a feral horse (a domestic horse which reverted to the wild).
There are some strong indications that the Tarpan was indeed a true wild horse. Zoologists failed to recognize its importance though, and scientifically describe it, while it was still around.
The Tarpan became extinct in the 19th century. So-called Tarpans exhibited in zoos and elsewhere are products of a reconstruction project and not authentic. The closest thing to the real Tarpan we have today is the Polish primitive horse, or Konik, which has been preserved from direct Tarpan descendants and is not the product of a breeding program that involved horses and ponies of different - and unrelated - breeds.