The Mandalorians were mostly around during the Old Republic era specially involved in a war against the Jedi during this time.
Their style of armor has been a staple of popularity among the saga, from Boba Fett to now Sabine in Rebels. The Mandalorians are a group of multiple species that follow one common culture. They follow a honor and pride code that basically led a war. The culture was an influence all the way down to the Clone Wars era, if you pay close attention to the way the Clone Trooper helmets were made, they have tons of Mandalorian influence in them.
There are tons of houses and factions of Mandalorians and below them are different clans who work under a house. Mandalor became overtaken by the Republic which eventually was taken over when the Empire was created.
In the context of Rebel it is mentioned that The Protectors A.K.A Mandalorians who split from the group, don't like the others and even call the family of Sabine, Traitors! This was just a mention of Sabine's past, but it also gave up a sense at how the state of the group is doing and who is on who's side.
BATTLE OF MYGEETO!
For anyone who has played Star Wars Battlefront 2, Mygeeto was a blizzard like industrial planet that you were able to play on in the game. It was more important during the clone war era but if you payed attention to Revenge of the Sith, the planet is show briefly during Order 66.
"The Battle of Mygeeto was one of the longest battles of the Clone Wars, lasting for two years beginning in 21 BBY. In 19 BBY, it became part of the Galactic Republic's Outer Rim Sieges to secure the planets of the Outer Rim Territories."
I haven't kept up with the latest comics about Kanon but I do believe that those go into this story and the journey he has been through with his late master. This is was just side backstory mention but now that is have been brought into Rebels, there is still some more history that could be explored there.