Fatto generale: 1590 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 1590 is the denominator of the 52^{nd} Bernoulli number.
Trivia: 1590 is an unremarkable number.
Data storica: May 8th is the day in 1924 that the Klaipėda Convention is signed formally incorporating Klaipėda Region (Memel Territory) into Lithuania.