Post Graduate (Master of Arts) in English Literature and Philosophy
Sometime in the dawn of the human era in MCU, Asgardinians visited Midgard i.e Earth and left the Tesseract here. As shown in Captain America: The First Avenger, head of Hydra, Johann Schmidt recovers the Tesseract in 1942 from its hiding place for a thousand years at a church in Tønsberg, Norway. It was hidden at the church under a mural of the Yggdrasil. Schmidt uses the Tesseract as an energy source to power the weapons designed by Dr Arnim Zola. After the final confrontation of Captain America with Schmidt on the Hydra bomber over the Arctic, the Tesseract falls into the ocean from where Howard Stark later retrieves it.
Presumably, it was brought the US by Howard Stark and handed over to the OSS, which would later become S.H.I.E.L.D. It is strongly implied that SHIELD continued experiments with the Tesseract under the supervision of Dr Arnim Zola who was recruited by SHIELD under Operation Paperclip (Captain America: The Winter Soldier).
During the 1990s
The next time, chronologically the MCU, the Tesseract turns up again in Captain Marvel. During the early 1980s, Dr Wendy Lawson initiated a project under the aegis of SHIELD to construct an aircraft engine capable of intergalactic travel at high speeds powered by the Tesseract. After the confrontation with Yon-Rogg, Lawson destroys the engine. Captain Marvel aka Carol Danvers gets caught in the blast wave and gets her powers in the process.
After Danvers regains her memory in 1995 and defeats Yon-Rogg, SHIELD, under the leadership of Nick Fury gains control of the Tesseract once again after losing it in 1989 when Dr Lawson died with the whereabouts of the Tesseract unknown.
The SHIELD apparently locked the Tesseract away for good after that incident.
The Recent MCU Era
After the events of Thor, Nick Fury was convinced that Earth needed better weapons to confront threats from outer space. In the post-credit scene, Nick Fury is shown to recruit Dr Erik Selvig to work on the Tesseract in order to utilize its energy to power new weapons, basically the same thing Schmidt tried to do with the help of Dr Zola. As Selvig started to tap into the Tesseract's power, its cosmic signature surged and it sent intergalactic signals to other realms that earth was ready for a "higher form of war".
Selvig's work initiates the events of the Avengers. Loki steals the Tesseract from a SHIELD facility and opens a portal through which his Chitauri army invades earth. After Loki is defeated by the Avengers, Thor takes the Tesseract back to Asgard where it was kept in Odin's trophy room. For the next few films, the Tesseract does not appear in the MCU, until Thor Ragnarok.
Seeing Asgards inevitable destruction at the hands of Surtur and Hela, Loki steals the Tesseract from the trophy room. Thanos retrieves the Space Stone from the Tesseract when he attacks the Asgardian refugee vessel after the events of Thor Ragnarok. He destroys the Tesseract and sets the space stone in his Infinity gauntlet after he destroys most of the Asgardian vessel. He uses the stones at the ending of Infinity War to wipe half of the population of the universe.
Sometime between the events of Infinity War and Endgame, Thanos uses the Infinity Stones for a second time to destroy the stones.
Going back in Time
In order to undo Thanos's snap, the Avengers in the events of Endgame planned a time-heist via a quantum time-portal. Tony, Steve along with Antman went back to 2012 during the battle of New York in order to retrieve the Tesseract from the past. Their attempt in 2012 fails and Loki escapes with the Tesseract. So Tony and Steve further went back in time, to 1970, to retrieve it from a SHIELD facility in New Jersey.
This time period is presumably set after the events of Captain America: The First Avenger and before Dr Lawson starts experiments with the Tesseract to construct the light-speed engine.
After the Avengers defeat Thanos in Endgame and the death of Tony Stark, Captain America journeys through the time-portal to keep the stones back at their respective timelines. So, it might be surmised that the Tesseract, along with the Space Stone is eternally caught in time-loop with a time-line divergence where Loki escapes with the Tesseract in 2012 creating an alternate timeline.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Abhijit Chatterjee