From The Collaborative International Dictionary of English v.0.48 :
Misdate \Mis*date"\, v. t. [imp. & p. p. Misdated; p. pr. &
vb. n. Misdating.]
1. To put a false or erroneous date on (a document). --Young.
[1913 Webster]
2. To assign an incorrect date to; as, the fall of Troy was
misdated by medieval writers.
[PJC]
From The Collaborative International Dictionary of English v.0.48 :
misdating \misdating\ n.
The assignment of a date to something at a time when it could
not have existed or occurred.
Syn: anachronism, mistiming.
[WordNet 1.5]
From WordNet (r) 3.0 (2006) :
misdating
n 1: something located at a time when it could not have existed
or occurred [syn: anachronism, mistiming, misdating]