This statement is repeated countless time on this forum-name John was not given among English Royal Family due to memory of John Lackland. But name 'John' was given to royal sons long after Softsword. It was common among Plantagenets and later also present among Yorks and Lancastrians. Also IIRC king John was viewed during Tudor times as English hero, who opposed the pope. So when name 'John' really became unacceptable for royal babies?