Giovanni Giustiniani Longo (Greek: Ιωάννης Λόνγος Ιουστινιάνης, Iōánnēs Lóngos Ioustiniánēs; Latin: Ioannes Iustinianus Longus; 1418 – 1 June 1453) was a Genoese nobleman, captain, and defender of Constantinople during its siege in 1453. He was instrumental in its defense and commanded 700 men, as well as leading the land forces protecting the city. Family and early life Giustiniani was a member of the powerful House of Doria and was probably native to the island of Chios. Although little is known of his origin, Giustiniani was known to be a mercenary soldier, and was an expert at defending besieged cities. Siege of Constantinople Upon hearing of the plight of Constantinople, Giustiniani (along with 700 men from Chios and Genoa) sailed to defend the city, arriving in late January to prepare for the siege. Constantine XI strategically placed this contingent to the right of his own position, and appointed Giustiniani to the rank of Protostrator. Constantine appointed Giustiniani as the leader of the city's land defenses, and prior to the siege he was tasked with training soldiers, reinforcing fortifications, and generally preparing for the imminent attack. Learning from the siege of 1422, he directed the defense efforts at the outer walls, with Archbishop Leonardo di Chio's suggestion that the inner walls be prioritized being dismissed due to their supposed disrepair. During this stage, there was no manpower deficiency, though it became clear that there would only be 8,000-9,000 people to defend Constantinople. Noting that the city lacked funds to pay its defenders, Constantine used church jewelry and silverware to mint coins to pay the soldiers. Giustiniani was placed on the right of the most strategic and lowest lying section of the walls, between St. Romanos and Charisius. Immediately, he reorganised the army, trained the city's recruits in modern weaponry, and removed men who had fled to monasteries with the hope of escaping military duties, instead directing them to Constantinople's defensive efforts. Giustiniani also reinforced the wall's most critical points with his 700 Genoese mercenaries. Upon Sultan Mehmed's arrival on April 6, Giustiniani began commanding sorties to counterattack the Ottoman position. These are recorded as being very successful, and resulted in the destruction of Ottoman troops, siege works and artillery. However, sorties were gradually abandoned due to their high death rates. His approach regarding wall repairs was also a hindrance to the Ottomans; his strategy involved cushioning the blow of artillery fire by