Christopher Columbus, if indeed he was born in Genoa, would have been called at birth "Cristoforo Colombo". His birth is postulated at between August and October of 1451. Today Genoa is part of Italy, but in 1451 it was an independent city-state, and the richest city in the western Mediterranean.
The native language of Genoa at that time was Ligurian. Columbus spoke several languages by the time he was an adult, including Latin, Portuguese, Spanish, and perhaps Catalan. So it is difficult to tie down his nationality from the languages he spoke in later life.
The Columbus documents available today include more than 2,500 notes penned in the margins of books he owned; some 80 letters, notes and memorials; copies of the log from his first New World voyage; volumes he compiled; and his will. Most of the books and manuscripts are in Spain, but there are important Columbus materials in Italy, France, and the United States.
The Provincial archive in Genoa has a Sala Colombiana, a small room that holds many original Columbus family documents. They have survived the events of five centuries, including Louis XIV's 1684 naval bombardment of Genoa. More than 60 documents recount the story of the Columbus family, beginning with the youth of Domenico Colombo. He was apprenticed to a Flemish weaver at the age of 11 and become a master weaver. Domenico Colombo married Susanna Fontanarossa. Their first child was Cristoforo, in 1451; later came Giovanni Pellegrino, Bartolomeo, Giacomo, and daughter Bianchinetta.
Christopher worked with his father. He first appears in the notarial record of September 1470; later that year, at "greater than nineteen years of age". By 1472 Columbus had learned his father's trade, for in that year he is called LANAIOLO, a worker in wool. It is not clear when he became a sailor, or why. "From a very early age," he states in a 1501 letter, "I entered sailing upon the sea and have continued it until today."
The Assereto document, named for the man who in 1904 recognized its importance, involves a 1479 lawsuit over a sugar transaction on the Atlantic island of Madeira. In it young Christopher swore that he was a 27-year-old Genoese citizen resident in Portugal and had been hired to represent the Genoese merchants in that transaction. This showed that he was living in Portugal in 1479
Historian Samuel Eliot Morison, in his book "Admiral of the Ocean Sea", notes that existing legal documents demonstrate the Genoese origin of Columbus. On page 14, Morison writes:
Domenico had a brother Antonio, like him a respectable member of the lower middle class in Genoa. Antonio had three sons: Matteo, Amigeto and Giovanni, who was generally known as Giannetto, the Genoese equivalent of "Johnny." Johnny like Christopher gave up a humdrum occupation to follow the sea. In 1496 the three brothers met in a notary's office at Genoa and agreed that Johnny should go to Spain and seek out his first cousin "Don Cristoforo de Colombo, Admiral of the King of Spain," each contributing one third of the traveling expenses. This quest for a job was highly successful. The Admiral gave Johnny command of a caravel on the Third Voyage to America, and entrusted him with confidential matters as well.
Columbus himself alludes to his birthplace. In 1502 he wrote from Spain to directors of Genoa's Bank of San Giorgio, offering an endowment to relieve the city's poor of the tax on food and wine. "Even though my body walks here," he wrote poignantly, "my heart is always there." Christopher Columbus appears to have donated one-tenth of his income from his discovery of the Americas to the Bank of San Giorgio in Genoa for the relief of taxation on foods.
Christopher Columbus, son Ferdinand says of his father: "He learned his letters at a tender age and studied . . . at the University of Pavia. The University of Pavia has no record that Christopher Columbus ever studied there. But it has been suggested that he may have attended a monestary school in a district of Genoa called Paverano, thus giving rise to the word "Pavia". Fernando wrote in his biography of his father Columbus, that he was Genoese; and his Genoese origin was also asserted by a family friend Bartolomé de Las Casas.
Other evidence of Columbus's Genoese origin include his will of February 22, 1498, in which Columbus wrote "yo nacio en Genoba" (I was born in Genoa). This will mentions a Genoese merchant who is also mentioned in the 1479 lawsuit mentioned above
However we can note:
Christopher Columbus - discoverer of America