Full Idea
While set theory was liberated much earlier from type restrictions, interest in type-free theories of truth only developed more recently.
Gist of Idea
Set theory was liberated early from types, and recent truth-theories are exploring type-free
Source
Volker Halbach (Axiomatic Theories of Truth [2011], 4)
Book Reference
Halbach,Volker: 'Axiomatic Theories of Truth' [CUP 2011], p.25
A Reaction
Tarski's theory of truth involves types (or hierarchies).