Published to coincide with The Sandman's 25th anniversary, The Sandman: Overture was a six issue miniseries that served as a prequel to the classic series. Written by Neil Gaiman with art by J.H. Williams III, this tells the tale of the great cosmic event that weakened Dream of the Endless enough so that he was susceptible to capture by simple hedge magic in The Sandman #1. When Morpheus made his original appearance in the first issue of Sandman, Gaiman alluded to some fantastical conflict that left the Lord of Dreams weakened and vulnerable. The series never explained what that conflict entailed, only that it left him weak and vulnerable. In The Sandman: Overture, Gaiman elected to explore the events which led up to the original series.
Originally intended to run bi-monthly, with its first issue published in October 2013. However, The Sandman: Overture was plagued by delays, and the final issue did not come out until 2015.