Background: The discovery of the pulmonary circulation represents a transformative journey in medical history, yet the contributions of key pioneers remain unevenly recognized. Although William Harvey is universally credited for his 1628 description of blood circulation, earlier groundbreaking descriptions by Ibn al-Nafis (1210-1288) and Michael Servetus (1511-1553) in countering Galen’s (129-216AD) long-established dogma deserve greater recognition. Methods: A narrative review of historical medical literature, including primary sources and contemporary scholarship on the evolution of circulatory physiology from Galen through the European Renaissance. Findings: Ibn al-Nafis described the pulmonary circulation in 1242, correctly rejecting Galen's septal pore theory and anticipating proof of there being pulmonary capillaries some 400 years before Marcello Malpighi (1629-1694). However, there is some recent evidence that suggests Persian physicians during the Sassanid era (224-637 AD) may have recognized pulmonary circulation even earlier. Servetus independently described the pulmonary circuit in 1553, though debate persists about possible transmission of Ibn al-Nafis's work through Arabic-to-Latin translations. Harvey's 1628 experimental demonstration established the closed-loop circulation, apparently without knowledge of his predecessors, as Ibn al-Nafis's work remained untranslated from Arabic until 1924. Conclusions: The history of the discovery of the pulmonary circulation exemplifies how scientific progress depends on challenging established dogma across cultures and centuries. However, the contributions of Ibn al-Nafis, Servetus, and possibly their predecessors, deserve recognition alongside Harvey and underline why historical research should be inclusive of other cultures and languages and avoid being anglo- or euro-centric.