The third season ends with the Queen celebrating her Silver Jubilee, for 25 years on the throne. Although she puts on a good face for her subjects, behind closed doors, she's feeling the strain and loneliness more than ever. Almost immediately before her big jubilee celebration, she takes a personal hit when her sister nearly dies, and a professional one when her trusty prime minister Harold Wilson tells her he's resigning soon.
In the last moments of the season, she heads out to the Jubilee festivities after a rare heart-to-heart with Margaret, but with a lot weighing on her. Margaret reminds her that she, as the monarch, must always stand above and alone. Elizabeth is fully settled in her role as monarch, but after having to enforce the rules of duty on her own family throughout the season, she's clearly disappearing more and more into the crown.