January 12, 1167: Aelred, the Anglo-Saxon abbot who became one of the Middle Ages' best-known devotional writers, dies.
January 13, 367 (traditional date): Hilary of Poitiers, the leading orthodox church father during Arianism's heyday, dies. His writings about the Trinity and his organization of anti-Arian allies were influential in fighting the heresy but did not have their full effect until after his death.
January 14, 1529: Spanish diplomat and writer Juan de Valdes publishes his "Dialogue on Christian Doctrine," which paved the way for Protestant ideas in Spain.
January 14, 1875: Theologian, medical missionary, organist, musical historian, and winner of the 1952 Nobel Peace Prize Albert Schweitzer is born. His Quest of the Historical Jesus (1906) is considered a foundational work on that subject.
January 15, 345 (traditional date): Paul of Thebes, traditionally considered the first Christian hermit and an inspiration for Antony of Egypt and later Christian monasticism, dies.
January 15, 1535: Henry VIII declares himself head of the English Church [actually he declared himself "defender of the faith"; that's a little different from being "head of the English Church." - ed.].
January 15, 1697: Massachusetts citizens observe a day of fasting and repentance for the Salem witch trials of 1692, in which 19 suspected witches were hanged and more than 150 imprisoned. The day was declared "That so all of God's people may offer up fervent supplications unto him, that all iniquity may be put away, which hath stirred God's holy jealousy against this land; that he would show us what we know not, and help us, wherein we have done amiss, to do so no more".
January 15, 1844: The University of Notre Dame, America's premiere Roman Catholic institution of higher learning, is chartered in South Bend, Indiana.
January 15, 1929: Baptist minister Martin Luther King, Jr., America's most visible civil rights leader from 1955 until his assassination in 1968, is born in Atlanta.
Information courtesy of Christianity Today