Some of the anthologies of essays, which include history, biography, memoir etc. were written before common era. (hubpages.com)
The main goal of Iso2k is to identify regional - and global - scale features in Common Era hydroclimate and atmospheric circulation and then assess possible relationships with temperature reconstructions [PAGES 2k Consortium, 2013, 2017; Tierney et al., 2015; McGregor et al., 2015; Abram et al., 2016]. (eos.org)
Overview: CE usually stands for Common Era. (myintimcity.com)