Question

In 1227, Genghis Khan, the Mongol leader who conquered much of Central Asia, died he was buried in an unmarked grave, and its location remains a mystery today.

is this a run on sentence

Answer 1

Yes, this is a run-on sentence.

Run-ons, comma splices, and fused sentences are all names given to compound sentences that are not punctuated correctly. The best way to avoid such errors is to punctuate compound sentences correctly.