Writer of the original Inspector Morse novels, Colin Dexter, made cameo appearances in the first three series of this show as well as the previous shows: Inspector Morse (1987) and Inspector Lewis (2006). He continues to make "appearances" even after his retirement and subsequent death in 2017: appearing on the set as a photograph, a caricature, a sculpture, a written reference to his name, etc.
Musical Morse: The inspector's last name, translated into Morse Code, reads as " - - / - - - / . - . / . . . / . " Impressively, this code is precisely reflected in theme music written by Barrington Pheloung, and is easily identified at the end of S1 Episode 2 (Fugue). In the final scene, as E. Morse looks on the sunset over the quad, bells begin to chime. Next, violins can be heard beginning a loop of the musical version of letters M.O.R.S.E., playing on a frequency of 329.63 Hz (tonal E in music). Soon, a masterful orchestration is woven in, diversifying this subtle nod to cryptography. Considering the content of the episode, this thematic and compositional brilliance is perfectly placed.
Abigail Thaw, daughter of John Thaw who played Inspector Morse, appears in several episodes of Endeavour as Dorothea Frazil. Frazil is a type of ice; when combined with the character's first initial the name could be read as De-ice, which in turn could be interpreted as to "thaw."
In the pilot, the character Dorothea Fraizil, played by Abigail Thaw, daughter of John Thaw, on her first meeting with the young Morse, says haven't we met before? He shakes his head and says no. As he walks away, she gazes warmly at him ... 'maybe in another life'.. We, the viewer, know she's referring to the daughter-father relationship'of older Morse, John Thaw.
The title of Endeavour: Pilot (2012) was revealed as "First Bus to Woodstock" by Damian Michael Barcroft in his website during an interview with actor Shaun Evans and another with writer Russell Lewis. This title references "Last Bus to Woodstock", which was the first Inspector Morse novel written by Colin Dexter published in 1975. Originally a standalone TV-movie, it is has since been rebroadcast on ITV3 as part of series 1, and could be counted as either episode 0 or episode 1.
Throughout its entire run, "Endeavour" not only includes references to the later set "Morse" and "Lewis", but also "Easter Egg" surprise references to British made TV programmes and Films, that some International viewers may understandably miss. The TV series references include series from both the BBC and ITV, either originally made, or set in a time period, contemporary to the historical setting within the "Endeavour" story universe.
In February 2016, ITV announced that a fourth series of Endeavour had been commissioned, which Roger Allam confirmed to the Oxford Mail, with filming to begin in late spring 2016. To mark the 30th anniversary of Morse on television, the series features several early Morse characters and cameos by actors from the original series. The fourth series debuted on 8 January 2017, and the fifth series began on 4 February 2018.
Roger Allam (DI Fred Thursday) and Anton Lesser (Chief Superintendent Bright) have both starred in Game of Thrones (2011). Furthermore, the pilot episode included two more cast members of the Emmy-winning program, Patrick Malahide and Ian Gelder. Also, Roger and Anton starred together in Pirates of the Caribbean: On Stranger Tides.
Curiosly, in the original Inspector Morse series Chief Superintendent Stranges office is full of naval memorabilia (a model of a sub, photos etc) as if he has a previous connection with the Royal Navy (his use of the word matey to Morse is a naval slang as well). No such connection is (so far) presented in Endeavour.
A region 2 DVD of the pilot at 89 minutes long was released on 9 January 2012, but, as reviewers have noted, does not contain the full show and many scenes aired on ITV have been cut out. A complete edition running at 98 minutes was released on 26 January 2012.
All episodes in the first six series have one-word titles. One word from each series is a musical term. In order, they are: Fugue, Nocturne, Coda, Canticle, Quartet, and Deguello. (The last is the most obscure; it is the name of a bugle call used by the Mexican army.)
It was announced on 5 June 2013 that due to the success of series 1, including consistently high ratings, ITV had commissioned a second series of four episodes. Filming commenced in Oxford in September 2013. On 24 September 2014, ITV confirmed that a third series of Endeavour had been ordered.