Crusader Rabbit was the very first cartoon
made for television
The concept, and the "limited animation" technique that made production cheap enough for TV, were the ideas of Alex Anderson. He first tried to get his uncle and boss, Terrytoon Studios (Mighty Mouse) founder Paul Terry, to back him, but was unsuccessful. He had better luck with his friend Jay Ward, who was making lots of money as a real estate agent at the time. Ward quit real estate, and the two formed Television Arts Productions in 1948. Ward was the business manager, producer, and sometimes a writer for the company, but Anderson was the animator.
By the end of the year, TAP had products to sell. They proposed three shows to NBC: Crusader Rabbit, Hamhock Jones, and Dudley Do-Right. NBC bought only the rabbit.
Anderson's concept of the TV cartoon was to use static backgrounds and minimal movement of the characters - the story was the thing. Crusader Rabbit was produced in five-minute episodes, serial-style, with cliffhanger endings. The voice of Crusader Rabbit was provided by Lucille Bliss, AKA (years later) Smurfette. TAP produced 195 episodes for the original black and white run of the show, at a production cost of about $2500 each. One of them featured a big, stupid moose named "Bullwinkle". Production ended in 1951, amid some legal hassles over ownership of the characters.
In 1957, NBC wanted to revive the series, in color this time, so Anderson sold them Crusader Rabbit, but retained the rights to the "minor characters" that TAP had created. They included Dudley Do-Right, Bullwinkle, and the rest of the "Frostbite Falls Review" (another rejected series idea).
Anderson had gone into advertising, but Jay Ward was smitten with TV cartoons. He convinced Anderson to sell him 50% of the rights to the TAP characters, then went back into real estate just long enough to get the money to start Jay Ward Productions, whose first show, Rocky and His Friends, became fairly popular.
After Wards's death, his estate began selling off pieces of the Bullwinkle empire, and Anderson sued them for his 50%. He won the suit, but Ward's estate still disputes Anderson's claim to the creation of the Rocky and Bullwinkle characters.