In 1615 German astronomer, mathematician and astrologer
Johannes Kepler first published the use of the culturally neutral expression "
common era" for year notations in his work with the following extremely verbose title:
Joannis Keppleri Eclogae chronicae: ex epistolis doctissimorum aliquot virorum & suis mutuis, quibus examinantur tempora nobilissima: 1. Herodis Herodiadumque, 2. baptismi & ministerii Christi annorum non plus 2 1/4, 3. passionis, mortis et resurrectionis Dn. N. Iesu Christi, anno aerae nostrae vulgaris 31. non, ut vulgo 33., 4. belli Iudaici, quo funerata fuit cum Ierosolymis & Templo Synagoga Iudaica, sublatumque Vetus Testamentum. Inter alia & commentarius in locum Epiphanii obscurissimum de cyclo veteri Iudaeorum. Frankfurt: Johann Bringer, 1615.
In this work, according to the Wikipedia, Kepler used the expression
annus aerae nostrae vulgaris or "year of our common era." The expression apparently first appeared in English as "Vulgar Era" in 1635 and as "Common Era" in 1708.
