The album's release was delayed several times by the band, in an attempt to find a record label who could provide international distribution simultaneously.

[3] The band were encouraged by Artery Recordings, their American label to move and base themselves in the United States but they refused as they had little experience in the country.

[6][7][1] Their music features a contrast between melodic and aggressive vocal styles, intricate guitar riffs, clean-sung choruses and breakdowns.

Jason Cameron's "soulful" voice is matched by a melodic background, and is quickly contrasted by the chaos that surrounds Dani Winter-Bates aggressive growling.

[11] Unlike their debut album, The Union of Crowns shows a melodic death metal influence, being comparable to As I Lay Dying.

[12] Lead vocalist Dani Winter-Bates, when asked how the music on the album sounds like he jokingly commented "basically if Michael Bolton joined Killswitch Engage."

[2] The band both headlined a stage at Southampton based Takedown music festival and was the main support for Of Mice & Men on their April tour of the UK.

[14] In these dates, Bury Tomorrow debuted their two new singles, "Lionheart" and "Royal Blood", as well as two brand new songs off the album at these live shows.

[27] In the United States, the album peaked on 4 August 2012 at number 25 on the Top Heatseekers chart and sold 1,062 copies all in its first week.

[28][29] Ahead of the release of the album, the band has planned to support Architects in November in a tour round Britain alongside Deez Nuts and The Acacia Strain.

[30] In cooperation with Monster Energy, a B-Side from the album, titled "Darkest Regions", was released as a free downloadable track on 26 December 2012.

Starting off the review stating "Bury Tomorrow doesn't reinvent the wheel on The Union of Crowns, but there are times when doing something well is its own form of progression.

"[8] Hoffmeyer, despite an otherwise positive review described it as being "frequently plagued by the mediocrity that weighed Portraits down", also saying the album's lack of innovation is shown in their strong influence by other metalcore bands, saying 'Message to a King' is "basically a Parkway Drive song with clean vocals.