First things first: the fashions on this show are ridiculous and amazing and you're damn right I'm going to be talking about them. One thing they are not, however: within spitting distance of historical accuracy, much like the show itself.
Second: how on EARTH do you pronounce Coachella? Co-AH-chella? Coach- ella? How many syllables are there? Do I even need to know? (For the record, my brain always says Co-AH-chella, which is probably wrong).
Anyway, Reign is CW's attempt to capitalize on Game of Thrones' popularity, only with actors who look like they've showered in the last decade and based on the real Mary, Queen of Scots. However, it appears just about the only thing they are keeping from actual history are the names, and they've jettisoned most of those too.
Now, a note: I am a historian* but definitely not of this era, and considering the massive liberties they are taking with this story I really can't tell you what happened and what didn't (although I'm fairly certain Francis did not spend some time hunting a woodland demon, which is a thing that happens in this show.) However, I do know the big stuff, that being: Mary did marry Francis, the crown prince of France, but he died shortly after their marriage. His mother, Catherine de Medici, maybe/possibly/almost certainly ordered the St. Bartholomew's Day Massacre, during which most of France's Protestant leaders were murdered AT HER OWN DAUGHTER'S WEDDING, which sparked days of Catholic violence against French Protestants and a death toll of some 10,000, and was overall a rather terrifying and badass Queen Regent.** After Francis' death, Mary left France and returned to Scotland where she married a series of good-for-nothing drunks and was arrested by England for plotting to overthrow her cousin, Elizabeth I of England, and spent her house arrest continuing those plots. Eventually, Elizabeth had to be all "Dammit, Mary, could you stop trying to overthrow me for, like, ONE SECOND?" and Mary was all "LOL, no" and then Elizabeth had her beheaded.***
*It's "a" historian not "an" historian and anyone who tells you otherwise is a pretentious asshole.
** Catherine de Medici: a real life Tywin Lannister, only way more hardcore.
*** Exact dialogue between these two 16th century monarchs has been painstakingly replicated here.
