What exactly did Mendel do?

-He simply first had a Tall Pea Plant, and crossed it with a Dwarf Pea Plant -This resulted in all the Offspring's being Tall -However, in the Second Cross [Took 2 Plants from the First Set] he found out that 3/4 of the Offspring's was Tall, so therefore the 'Inherited Factors' [Genes] was Passed on from the Parent. And he also showed that the Tall Inherited Factor was Dominant over the Small, which was Recessive