Pope Saint Julius I, was pope from 6 February 337 to 12 April 352.

He was a native of Rome and was chosen as successor of Mark after the Roman seat had been vacant for four months. He is chiefly known by the part he took in the Arian controversy. After the followers of Eusebius of Nicomedia, who was now the Patriarch of Constantinople, had renewed their deposition of Athanasius as bishop of Alexandria, at a synod held in Antioch in 341, they resolved to send delegates to Constans, Emperor of the West, and also to Julius, setting forth the grounds on which they had proceeded. Julius, after expressing an opinion favourable to Athanasius, adroitly invited both parties to lay the case before a synod to be presided over by himself. This proposal, however, the Arian Eastern bishops declined to accept.

On this second banishment from Alexandria, Athanasius came to Rome, and was recognised as a regular bishop by the synod presided over by Julius in 342. Julius sent a letter to the Eastern bishops that is an early instance of the claims of primacy for the bishop of Rome. Even if Athanasius and his companions were somewhat to blame, the letter runs, the Alexandrian Church should first have written to the pope. "Can you be ignorant," writes Julius, "that this is the custom, that we should be written to first, so that from here what is just may be defined" (Epistle of Julius to Antioch, c. xxii).

Pope Julius II (5 December 1443 – 21 February 1513), nicknamed "The Fearsome Pope" (Il Papa Terribile) and "The Warrior Pope" (Il Papa Guerriero), born Giuliano della Rovere, was Pope from 1503 to 1513. His papacy was marked by an active foreign policy, ambitious building projects, and patronage for the arts.

There is disagreement about Julius' date of birth. Some sources put his birth as late as 1453. Giuliano della Rovere was the son of Rafaello della Rovere brother of Pope Sixtus IV and of Theodora Manerola, a lady of Greek extraction. Giuliano was an altar boy of his uncle Pope Sixtus IV (Francesco della Rovere). He was educated among the Franciscans by his uncle, who took him under his special charge and later sent him to a convent in La Pérouse with the purpose of obtaining knowledge of the sciences. However, he does not appear to have joined the order of St. Francis, but rather remained a member of the secular clergy until his elevation to bishop of Carpentras, France, in 1471; very shortly after his uncle succeeded to the papal chair.

Pope Julius III (10 September 1487 – 23 March 1555), born Giovanni Maria Ciocchi del Monte, was Pope from 7 February 1550 to 1555.

In his early career in the Church Julius established a reputation as an effective and trustworthy diplomat, and was elected to the Papacy as a compromise candidate when the Papal Conclave found itself deadlocked between the rival French and German factions. As Pope he lost, or failed to show, any of the qualities which had distinguished his previous career, devoting himself instead to a life of personal pleasure and indolence, and the achievements of his incumbency were very few. His lasting fame, or notoriety, rests rather on his relationship with the 17 year old boy whom he raised to the position of Cardinal-Nephew, and, it was said at the time, with whom he shared his bed: the resulting scandal did great harm to the reputation of the Church.

The last of the High Renaissance Popes, Julius III was born Giovanni Maria Ciocchi del Monte in Rome in 1487. His father was a famous jurist; and he himself studied law at Perugia and Siena, as well as theology under the direction of the Dominican, Ambrosius Catharinus.

Leonardo di ser Piero da Vinci (Italian pronunciation: [leoˈnardo da ˈvintʃi]  pronunciation (help·info); April 15, 1452 – May 2, 1519, Old Style) was an Italian Renaissance polymath: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist, and writer whose genius, perhaps more than that of any other figure, epitomized the Renaissance humanist ideal. Leonardo has often been described as the archetype of the Renaissance Man, a man of "unquenchable curiosity" and "feverishly inventive imagination". He is widely considered to be one of the greatest painters of all time and perhaps the most diversely talented person ever to have lived. According to art historian Helen Gardner, the scope and depth of his interests were without precedent and "his mind and personality seem to us superhuman, the man himself mysterious and remote". Marco Rosci points out, however, that while there is much speculation about Leonardo, his vision of the world is essentially logical rather than mysterious, and that the empirical methods he employed were unusual for his time.

John Julius Cooper, 2nd Viscount Norwich CVO (born 15 September 1929) — known as John Julius Norwich — is an English historian, travel writer and television personality.

Norwich is the son of the Conservative politician and diplomat Duff Cooper and of Lady Diana Cooper, a celebrated beauty and society figure. Through his father, he is descended from King William IV and his mistress Dorothea Jordan.

He was educated at Upper Canada College, Toronto, Canada (as a wartime evacuee), at Eton College, and at the University of Strasbourg. He served in the Royal Navy before taking a degree in French and Russian at New College, Oxford.

Joining the British Foreign Service after Oxford, John Julius Cooper served in Yugoslavia and Lebanon, and as a member of British delegation to the Disarmament Conference in Geneva. At his father's death in 1954, he inherited the title of Viscount Norwich, created for Duff Cooper in 1952, which made him a member of the British House of Lords.

In 1964, Norwich left the diplomatic service to become a writer. Apart from his many books (see list), he has also served as editor of series such as Great Architecture of the World, The Italian World, The New Shell Guides to Great Britain, The Oxford Illustrated Encyclopaedia of Art and the Duff Cooper Diaries. Norwich has often contributed to Cornucopia, a magazine devoted to the history and culture of Turkey.