Question: Which Saint, known as the "Apostle of the Apostles," was credited for two epistles in the Bible? 

Context paragraphs:
Five Pauline Epistles, A New Translation: The Five Pauline Epistles, A New Translation is a partial Bible translation produced by Scottish scholar William Gunion Rutherford, of five books of the New Testament.  The Bible books that were translated into English by Rutherford are a number of Pauline Epistles or "didactic letters", believed to be written by the Jewish Christian Apostle Paul.  The work was a translation of the Bible books of Romans, first and second Thessalonians, and first and second Corinthians, with a brief analysis.  The work was commenced in 1900, and was completed in 1908.  The entire work was brought together in one volume in 1984.

Saint Peter: Saint Peter (Syriac/Aramaic: ܫܸܡܥܘܿܢ ܟܹ݁ܐܦ݂ܵܐ, "Shemayon Keppa", Hebrew: שמעון בר יונה‎ ‎ "Shim'on bar Yona" , Greek: Πέτρος  "Petros" , ; r. AD 30; d. between AD 64 and 68), also known as Simon Peter, Simeon, or Simōn ( ), according to the New Testament, was one of the Twelve Apostles of Jesus Christ, leaders of the early Christian Great Church.  Hippolytus of Rome, a 3rd-century theologian, gave him the title of "Apostle of the Apostles".  According to Catholic teaching, Peter was ordained by Jesus in the "Rock of My Church" dialogue in Matthew .  He is traditionally counted as the first Bishop of Romeor popeand also by Eastern Christian tradition as the first Patriarch of Antioch.  The ancient Christian churches all venerate Peter as a major saint and as the founder of the Church of Antioch and the Roman Church, but differ in their attitudes regarding the authority of his present-day successors.

Bible translations into Lithuanian: The first small fragments of Bible and few Bible terms were probably translated as early as the 14th century, together with the baptism of Lithuania.  The first texts of the Holy Scriptures in the Lithuanian language appeared in the middle of the 16th century following the spread of the Reformation.  The first book in Lithuanian, "The Catechism" by Martynas Mažvydas, published in 1547, contained ten commandments of God, two psalms, extracts from the Gospels and the epistles of apostles.  In 1579-1580 Jonas Bretkūnas completed translation of the Bible, but it was not published.  Samuel Bogusław Chyliński printed a Bible in Oxford in 1659.  Prepared by a great number of Protestant translators (Johann Jakob Quandt, Jonas Berentas, Petras Gotlybas Milkus, Pilypas Ruigys, Adomas Fridrichas Simelpenigis and others), the Lithuanian Bible was first published in 1735 in Königsberg (in Lithuanian, Karaliaučius).

Authorship of the Petrine epistles: The authorship of the Petrine epistles (First and Second Peter) is an important question in biblical criticism, parallel to that of the authorship of the Pauline epistles, since scholars have long sought to determine who were the exact authors of the New Testament letters.  Most scholars today conclude that Saint Peter was not the author of the two epistles that are attributed to him and that they were written by two different authors.

Apostle (Latter Day Saints): In the Latter Day Saint movement, an apostle is a "special witness of the name of Jesus Christ who is sent to teach the principles of salvation to others."  In many Latter Day Saint churches, an apostle is a priesthood office of high authority within the church hierarchy.  In many churches, apostles may be members of the Quorum of the Twelve and First Presidency of the church.  In most Latter Day Saint churches, modern-day apostles are considered to have the same status and authority as the Biblical apostles.

Epistles to the Corinthians: There are two Epistles to the Corinthians in the Bible:

Pauline epistles: The Pauline epistles, Epistles of Paul, or Letters of Paul, are the 13 New Testament books which have the name Paul (Παῦλος) as the first word, hence claiming authorship by Paul the Apostle.  Among these letters are some of the earliest extant Christian documents.  They provide an insight into the beliefs and controversies of early Christianity and as part of the canon of the New Testament they are foundational texts for both Christian theology and ethics.  The Epistle to the Hebrews, although it does not bear his name, was traditionally considered Pauline for a thousand years, but from the 16th century onwards opinion steadily moved against Pauline authorship and few scholars now ascribe it to Paul, mostly because it does not read like any of his other epistles in style and content.  Most scholars agree that Paul really wrote seven of the Pauline epistles, but that four of the epistles in Paul's name are pseudepigraphic; scholars are divided on the authenticity of two of the epistles.

Epistle: An epistle ( ; Greek ἐπιστολή, "epistolē," "letter") is a writing directed or sent to a person or group of people, usually an elegant and formal didactic letter.  The epistle genre of letter-writing was common in ancient Egypt as part of the scribal-school writing curriculum.  The letters in the New Testament from Apostles to Christians are usually referred to as epistles.  Those traditionally attributed to Paul are known as Pauline epistles and the others as catholic (i.e., "general") epistles.

Apostles: In Christian theology and ecclesiology, the apostles (Greek: ἀπόστολος , "apóstolos ", 'one who is sent away' ), particularly the Twelve Apostles (also called the Twelve Disciples), were the primary disciples of Jesus, the central figure in Christianity.  During the life and ministry of Jesus in the 1st century AD, the apostles were his closest followers and became the primary teachers of the gospel message of Jesus.  The word "disciple" is sometimes used interchangeably with "apostle"; for instance, the Gospel of John makes no distinction between the two terms .  In modern usage, prominent missionaries are often called apostles, a practice which stems from the Latin equivalent of "apostle", i.e. "missio ", the source of the English word "missionary".  For example, Saint Patrick (AD 373–463) was the "Apostle of Ireland", and Saint Boniface (680–755) was the "Apostle to the Germans".

Apostle spoon: An apostle spoon is a spoon (usually silver or silver-plated, but sometimes of other metals, such as pewter) with an image of an apostle or other saint as the termination of the handle, each bearing his distinctive emblem.  Apostle spoons were particularly popular in Pre-Reformation times when belief in the services of a patron saint was still strong.  They symbolize the Last Supper of Christ in the company of the Apostles.  Apostle spoons were especially popular in England, but were also found in large numbers in Germany.

Supporting paragraphs: Authorship of the Petrine epistles Saint Peter
Answer: Saint Peter