Translation:In the old days many black cats died at Shrovetide, because one believed they were evil.
'Man' here must equal 'people'. To translate 'man' as 'one' is in most cases ridiculous. Only HRH The Qeen and I use 'one', and then we mean 'I', not plebs in general. Anyway, it's yet another case where finding a s**t translation illustrates something learnable about Danish.