Sarkel (or Šarkel, literally "white house" in the Khazar language) was a large limestone-and-brick fortress in what is now Rostov Oblast of Russia, on the left bank of the lower Don River.
It was built by the Khazars with Byzantine assistance in the 830s or 840s. It was named Sarkel, or 'white-house', because of the white limestone bricks used in its construction.
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