Complex sentence: The battle was later reported back to Europe by Marco Polo, who described the battle vividly in his reports in a description presumably pieced together by accounts he heard while visiting the court of Kublai Khan.
Split into simpler sentences: The battle was later reported back to Europe by Marco Polo, who described the battle vividly in his reports. His description was presumably pieced together by accounts he heard while visiting the court of Kublai Khan.