User blog comment:Woest/The Light and Darkness of the Guild/@comment-3424593-20140315170029/@comment-24066070-20140316071152

Zeref being on Tenrou Island could have something to do with his connection to Mavis, perhaps she told him he would not be able to kill many ppl over there, since hardly anyone sets foot on the island. It could be he didn't intentially kill Mavis, but that his magic went out of control at the wrong moment.

Makarov stated that Lumen Histoire was what Mavis wrote about the true nature of the Guild, so I consider this proof she was responsible for the creation of the "current" Lumen Histoire. If it turns out to be a Book of Zeref, then it's Zeref who created it and Mavis merely edited it.