 When Boisserée saw the painting he recorded the inscription 's date as 1480 . The last digit of the inscription was faded and difficult to read and had become illegible by 1899 . Waagen suggested the date could have been 1482 , and art historian Dirk de Vos suggested 1489 . Memling 's style does not lend itself well to assigning dates , making a determination difficult . According to Stirling , an earlier date is easily accepted , especially because of stylistic similarities to Memling 's 1479 St John Altarpiece , whereas Ainsworth leans toward the later date as more in keeping with the mature style of the late 1480s . 
