Purpose: Appreciating the relationship between Sylvio Ceccato and Ernst von Glasersfeld, both as people and in their work. Approach: historical and personal accounts, archeological approach to written evidence. Findings: Ceccato’s work is introduced to an English speaking audience, and the roots of Glasersfeld’s work in Ceccato’s is explored. Flaws in Ceccato’s approach are indicated, together with how Glasersfeld’s work overcomes these, specially in language and automatic translation, and what became Radical Constructivism. Conclusion: Glasersfeld willingly acknowledges Ceccato, who he still refers to as the Master. But Ceccato’s work is little known, specially in the English speaking world. The introduction, critique and delineation of extension and resolution of Ceccato’s ideas in Glasersfeld’s work is the intended value of the paper.