O'Connor, Daniel William (2013). "Saint Peter the Apostle". Encyclopædia Britannica. Encyclopædia Britannica Online. p. 5. [M]any scholars… accept Rome as the location of the martyrdom and the reign of Nero as the time.
"From an historical perspective, there is no conclusive documentary evidence from the 1st century or the early decades of the second of the exercise of, or even the claim to, a primacy of the Roman bishop or to a connection with Peter, although documents from this period accord the church at Rome some kind of pre‑eminence" (Emmanuel Clapsis, Papal Primacy, Orthodoxy in Conversation-eko erauzkina (2000), p. 110); and "The see of Rome, whose prominence was associated with the deaths of Peter and Paul, became the principle center in matters concerning the universal Church" (Clapsis, p. 102). The same writer quotes with approval the words of Joseph Ratzinger: "In Phanar, on 25 July 1976, when Patriarch Athenegoras addressed the visiting pope as Peter's successor, the first in honor among us, and the presider over charity, this great church leader was expressing the essential content of the declarations of the primacy of the first millennium" (Clapsis, p. 113).
Collins, Roger. Keepers of the keys of heaven: a history of the papacy. Introduction (One of the most enduring and influential of all human institutions, (...) No one who seeks to make sense of modern issues within Christendom – or, indeed, world history – can neglect the vital shaping role of the popes.) Basic Books. 2009. ISBN978-0-465-01195-7
Faus, José Ignacio Gonzáles. "Autoridade da Verdade – Momentos Obscuros do Magistério Eclesiástico". Capítulo VIII: Os papas repartem terras – Pág.: 64–65 e Capítulo VI: O papa tem poder temporal absoluto – Pág.: 49–55. Edições Loyola. ISBN85-15-01750-4. Embora Faus critique profundamente o poder temporal dos papas ("Mais uma vez isso salienta um dos maiores inconvenientes do status político dos sucessores de Pedro" – pág.: 64), ele também admite um papel secular positivo por parte dos papas ("Não podemos negar que intervenções papais desse gênero evitaram mais de uma guerra na Europa" – pág.: 65).
