Although Beets' suggestion of kinship was conjectural and without any direct evidence, it was picked up by Geoffrey Callender in the Mariner's Mirror in 1963 and has been relayed by several other authors.[4] The will of William Anthony did not mention any other sons and Anthonisz. is believed to have been the son of Antonis Egbertson, the daughter of Jacob Corneliszoon van Oostzanen. That Cornelis and Anthony were related is, in the words of Ann Payne, "not, presumably, impossible, but there is little evidence that they were connected at all".[5]