Joseph S. Rowntree has written:

'The Quaker peace testimony'

Testimony is the correct spelling.

Members of the Church across the world bear testimony of living prophets and apostles and speak of the blessings of peace and hope that arise from that knowledge.

The Testimony was created in 1931.

Corroborating a testimony means providing additional evidence or testimony that supports or confirms the original testimony given. It helps to strengthen the credibility and reliability of the original testimony by showing consistency and agreement from multiple sources.