Simplify the following text for a Grade 13 native English-speaking person.
Original: But as Sheridan Morley perceptively remarked in 2000 , when reviewing Cressida : `` Gambon 's eccentricity on stage now begins to rival that of his great mentor Richardson '' .
Simplified: But as Sheridan Morley perceptively remarked in 2000 , when reviewing Cressida : â Gambon 's eccentricity on stage now begins to rival that of his great mentor Richardsonâ .