from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
NON ASSUMPSIT INFRA SEX ANNOS. The name of a plea by which the defendant
avers that he did not assume to perform the assumption charged in the
declaration within six years.
2. The act of limitation bars the recovery of a simple contract debt
after six years; when a defendant is sued on such a contract, and it is more
than six years since he entered into the contract, he pleads this plea by
the following formula: "and saith that the aforesaid plaintiff the action
aforesaid hereof against him he ought not to have, because he saith that he
did not undertake, &c., and this he is ready to verify." Vide _dio non
accrevit infra sex annos.