Simplify the following text for a Grade 6 native English-speaking person.
Original: Tony the Tiger has been the mascot in Frosted Flakes since it was first introduced in 1952 as Sugar Frosted Flakes ( the word `` sugar '' was dropped in the mid-1970s ) , and he is known for saying the cereal 's slogan : `` They 're grrreat ! '' .
Simplified: The cereal was first introduced in 1952 as Sugar Frosted Flakes .