April 4

Hermann Cohen, founder of the Marburg school of neo-Kantian philosophy and author of Religion of Reason, died in Berlin.

The Roman emperor Caracalla, later remembered for the edict extending citizenship across the empire, was born on this day at Lugdunum in Gaul.

Ambrose of Milan, the bishop whose preaching helped draw Augustine to the faith and who shaped early Latin hymnody, died in Milan.

Isidore of Seville, archbishop and compiler of the encyclopedic Etymologiae that preserved much classical learning, died in Seville.

In newly founded Fatimid Cairo, work began on the al-Azhar mosque, which would grow into one of the oldest continuously active centres of Islamic learning.

The philosopher-yogi Sri Aurobindo arrived by steamer in Pondicherry, beginning the four decades of contemplative work that produced his integral philosophy.

Chögyam Trungpa, a Tibetan teacher of the Kagyu and Nyingma lineages who founded a network of meditation centers in the West, died in Halifax, Nova Scotia.