I can give you an off hand brief readers digest version, but this is limited in understanding for those without any back ground knowledge.
Cartilage, muscle, bone, bony armor, and tendons evolved together in fish as size speed and strength became advantageous for survival in a competitive world. Early fish which are main cartilaginous were the first to develop tendons. The early tendons were linear collagen fibers, which progressively became flat larger tendons. strengthening the muscle attachments, which gives the opportunity for better strength and speed. Cartilage evolved to bone for the advantage of supporting size and strength.
Tendons evolved before bone.
By the way the evolution of eyes follows the same scenario, beginning with simple light sensitive cells to better and more complex eyes had distinct survival value in both predators and prey in the race for survival.