There have always been plenty of gay and lesbian historical figures, but transgender history can be a little bit trickier to pin down. This is partly because the gender binary is so slippery to begin with. Are there any transgender historical figures? How do we even determine, in some cases, if a person from history was really trans or not? If a person from history had sexual or romantic relationships with people of the same sex, then we know that person was probably lesbian, gay, or bisexual. Gender expression can take more subtle forms, though, and those forms are often influenced by cultural norms and assumptions about what it means to be masculine or feminine. In Western culture, it has not been uncommon for celebrities and public figures who express their gender in unusual ways to be misunderstood, dismissed as mentally ill, or otherwise marginalized.
Below is a list of trans historical figures from throughout LGBT history - people who were assigned one gender at birth, and lived their lives (or parts of their lives) conforming to a different one. Some of them were openly transgender, some were genderfluid or nonbinary, and several kept their trans identities secret, sometimes for their entire lives. A few of these famous transgender people in history are open to speculation, and in some cases, these people lived so long ago, in times and places where gender was understood so differently, that we may never know for sure what version their personal "transitioning" journey was taking.
It's definitely clear, though, that gender dysphoria and radical gender variance aren't just new phenomena being embraced by trendy teenagers. Transgender and non-binary identities have been around for awhile, even in cultures like America today, where they've historically been considered abnormal, and sometimes unacceptable.