The 'decade' of the 1920s runs from January 1, 1920 to December 31, 1929.
There have been a lot of changes during/in/over the past two 'decades'.
a 'decade' of drought [=a drought that lasted 10 years]
(..) is to use our armies. Forgive me for asking, but why did you bother to bring your own? The Unsullied will have another objective. For decades, House Lannister has been the true power in Westeros. And the seat of that power is Casterly Rock. Grey Worm and the Unsullied (..)2017 TvShow: Game of Thrones Title: Stormborn Season: 7 Episode 2