I think it might be an archaic way of saying anon. I found a page of a poem about Robin Hood.
he is trew to his maister
sed our kyng
i sey by swete seynt john
he lovys better robyn hode
than he does us ychon
In more modern english
He is true to his master
said our king
i say by sweet St. John
he loves better Robin Hood
than he does us anon.
Where I found it