Timeline

Over 6,000 years ago

 * Ruby, Sapphire, Pearl, and Bismuth are created on the Gem Homeworld.
 * Gems arrive on Earth to establish a colony.


 * Blue Diamond establishes her court and oversees the construction of the colony.
 * Centipeetle and her crew members travel to Earth in the Ancient Gem Colony Ship.

Over 5,750 years ago

 * Rose Quartz was created on Earth


 * The Rebellion begins.


 * Sapphire is sent to Earth along with 3 Ruby guards, including the one soon to become Garnet. Sapphire gives Blue Diamond her prediction of the rebelling Gems.
 * The Crystal Gem's direct attack on Blue Diamond occurs.
 * Garnet is formed for the first time.
 * Garnet becomes a Crystal Gem.
 * Ruby and Sapphire decide to stay fused as Garnet based on advice from Rose.

Near 5,500 years ago

 * The two Kindergartens were shutdown

Over 5,300 years ago

 * Lapis Lazuli is caught in mid-war and is poofed during battle, and then collected by a Homeworld warrior, mistaken to be part of the Rebellion forces and put in a mirror for information to be given by her.

Over 5,000 years ago

 * A battle occurs at the location which would later become the Strawberry Battlefield. Many Gem Warriors fall. Rose's scabbard is lost.
 * Bismuth was bubbled by Rose, and left in Lion's pocket dimension
 * Pearl was "a few thousand years old" at the time.
 * Forced Fusion Experiments start.
 * The Cluster was embedded in the Earth's core at some point in these experiments.
 * The Pyramid Temple is constructed.
 * Homeworld Gems leave Earth.
 * Lapis Lazuli's mirror is abandoned at the Galaxy Warp and her gem is cracked during the evacuation.
 * A flash of light is set off by the diamonds, corrupting Gems caught in it, including Centipeetle and her crew. The only known survivors are Rose Quartz, Pearl, Garnet, Amethyst, Bismuth, and Lapis Lazuli.

Unknown Time Period

 * The Galaxy Warp goes inactive.
 * Pearl finds Lapis Lazuli's mirror in the Galaxy Warp.
 * The Crystal Temple is constructed.
 * Amethyst is discovered at the Kindergarten and joins the Crystal Gems.
 * Homeworld's resources become limited as Era 2 of gem production begins.
 * Peridot is created on Homeworld.

19th century

 * "Nearly 200 years ago", Captain William Dewey and his crew are attacked by a gem monster and rescued by an unknown fusion gem. Dewey goes on to found Beach City.
 * In the summer of 1862, William Buford Buchanan, Beach City's most notorious arsonist, sets a record of 335 fires. He drowns after diving into the ocean trying to evade police.

20th century

 * In 1965, the author of the No Home Boys, Dustylegs Jefferson, died tragically when he was hit by a train full of circus animals at a book signing in active train yard.

Recent History

 * Ocean Town is abandoned after an unspecified catastrophe.
 * Greg drops out of community college to become a professional musician and tour the country.
 * Greg records Space Train to the Cosmos.
 * Roughly two decades before Year 1, Greg falls in love with Rose Quartz and decides to stay in Beach City. He was 22 at the time.
 * Several months later, Greg records a music video with the Crystal Gems, learns about fusion and unsuccessfully attempts to fuse with Rose Quartz.
 * Greg starts growing a beard and records "Let Me Drive My Van (into Your Heart)".
 * Over a decade before Year 1, Rose Quartz records a video for Steven.
 * 12 years before Year 1, Rose Quartz gives up her physical form to give birth to Steven Universe.
 * Roughly 5 years before Year 1, the restaurant Aqua-Mexican goes out of business.
 * Over 4 years before Year 1, construction begins on the Beach House.
 * Two summers before the start of Season 1, Sadie started working at the Big Donut as a summer job.
 * Roughly 1 year before Year 1, Connie Maheswaran and Steven see each other for the first time at the Boardwalk Parade.
 * A year before the events of "Steven and the Stevens" (And two before "Sadie's Song"), Steven performs in his underwear (or possibly naked) at Beach-a-Palooza.
 * The summer before "Gem Glow" Sadie starts working at the Big Donut.

1st Year

 * Dogcopter 3 premieres in February, placing the events of "Lion 2: The Movie" at some point during that month or in early March.
 * "An Indirect Kiss" occurs right before the events of "Mirror Gem" and "Ocean Gem".
 * "Mirror Gem" takes place on the first day of summer vacation, which is June 25. That places the events in the first half of season 1, including Beach-a-Palooza, from "Steven and the Stevens", in spring.
 * "Horror Club" appears to have taken place on or around Halloween.
 * "Winter Forecast" takes place during December.
 * "Maximum Capacity" takes place around Beach City's annual New Year's fireworks, marking the end of the year.

2nd Year

 * "Marble Madness" takes place in early spring. The first spring buds can be seen on the trees around the Maheswarans' townhouse.
 * "Open Book", "Story for Steven" and "Shirt Club" take place before "The Return" and "Jail Break".
 * "Full Disclosure" takes place right after the events of "Jail Break".
 * "Joy Ride" takes place a few months after the events of "Fusion Cuisine".
 * Peridot is found during "Keeping it Together", a while after the events of "Full Disclosure".
 * In "Onion Friend", there's a schedule showing when Yellowtail will be home. Based on the crossed out dates on the chart, making it take place at some point in June, before Yellowtail's expected return on the 25th.
 * "Nightmare Hospital" occurs almost a year after the events of "An Indirect Kiss", in the summer, as mentioned by Connie.
 * "Sadie's Song" occurs roughly a year after "Steven and the Stevens", since Beach-a-Palooza is an annual event.
 * "Back to the Barn" starts right after the end of "When It Rains".
 * "Too Far" starts 3 days after "Back to the Barn".
 * "The Answer" and "Steven's Birthday" take place on Steven's 14th birthday, on August the 14th. Connie is "12 and 3/4" at the time.
 * "It Could've Been Great" takes place several weeks after "Catch and Release".
 * "Message Received" appears to start in the early morning after "It Could've Been Great", and "Log Date 7 15 2" appears to start during the daytime, soon after "Message Received".
 * The flashback portions of "Log Date 7 15 2" span several weeks.
 * Peridot makes her 7 11 2 entry immediately after Steven gives her the voice recorder, placing it before the beginning of "Too Far".
 * In her 7 12 2 entry, Peridot mentions that it's been 30 Earth days since she was captured in Catch and Release.
 * She makes an undated log entry after watching a "Camp Pining Hearts" tape for 78 hours.
 * The 7 14 2 entry takes place after Opal lifts up the nearly completed drill, placing it during the same timeframe as It Could've Been Great, between the end of the Peace and Love on the Planet Earth montage and the scene where everyone shows Steven the completed drill.
 * She makes the 7 15 2 entry at the start of the episode, and describes the events in "Message Received" as having just happened.
 * Fall is arriving in "Same Old World", as stated by Steven.

Level 2 Canon

 * Attack the Light, as well as the comics take place at an unspecified point between "Fusion Cuisine" and "The Return", placing it in Year 1 or Year 2.
 * The main portion of Too Cool for School takes place in June of Year 2.

Non-Canon

 * "Say Uncle" is set before "Story for Steven". Garnet still has her pre-regeneration outfit.