Sentence Correction

Although malaria was once universally believed to have been introduced to Native American populations by 16th-century European explorers, the recent excavation of a 10th-century mass grave of Native American malaria victims has caused many historians to reconsider their chronologies of European incursion into the Americas.


malaria was once universally believed to have been


malaria was at one time universally believed as being


malaria, once universally believed to be


malaria was at one time universally believed as having been


malaria, once universally believed as being