The Fandom Post is reporting that Cocoro has added all 52 episodes of the Princess Knight anime to its service. The episodes are available with an English dub for U.S. and Canadian viewers.
The series originally ran for 52 episodes between 1967 and 1968 as animated by Mushi Production.
The story of Princess Knight is described as:
Once upon a time, in the faraway kingdom of Silverland, a princess named Sapphire was born. Thanks to the prank of a mischievous little angel, Sapphire ended up with both the blue heart of a boy and the pink heart of a girl. Thus, the new little princess would be as rambunctious and brave as she was gentle and caring.
However, all was not well in Silverland. By law, only a son could inherit the throne. So, to stop the evil Duke Duralumon from being next in line to rule the kingdom, the King announced to his subjects that Sapphire was a boy.
Now, several years later, everyone in the kingdom sees Sapphire as a swashbuckling prince. Very few people know her secret. But the Duke still lurks in the shadows, waiting for a chance to make his move… So begins the story of Sapphire – the courageous Princess Knight – as she fends off the Duke’s wicked schemes and fights for justice and the happiness of her people.
Source: The Fandom Post