Importance: The recognition of the pulmonary circulation is a complex evolution in medical history and draws on theories across eras and cultures.
Observations: This narrative review summarizes evidence suggesting that the recognition of pulmonary circulation is older than the time of Ibn Nafis. The theory of pulmonary circulation originated in ancient Persia (ad 224-637), was overshadowed by Greek theory from the 11th century, and reestablished by Ibn Nafis in the 13th century.
Conclusions and relevance: The findings of this review may help contextualize the story of the discovery of pulmonary circulation in ancient Persian and Greek theories before Ibn Nafis.