The Three Musketeers (American TV series)

The Three Musketeers is an American Saturday morning cartoon produced by Hanna-Barbera Productions for NBC. It premiered in 1968, running for 18 episodes as a segment on The Banana Splits Adventure Hour. The cartoon is based on the 1844 novel The Three Musketeers by Alexandre Dumas.
Lady Constance appears in the third season of ''Jellystone!''

Premise

Athos, Porthos, Aramis, and D'Artagnan partake in new adventures fighting the enemies of the crowned heads of France King Louis XIII and Queen Anne.
The musketeers are sometimes assisted by a queen's handmaid named Lady Constance Bonacieux and her young nephew Tooly. A recurring theme has Tooly trying to prove himself worthy of becoming a Musketeer but the Musketeers will not allow him into their services because of his age. Tooley, who has a white horse, named Lightning, does get a present from the Musketeers, a mule for his birthday. Several of the cartoons end with the slogan "All for one, and one for all".