I agree with ADT that Maciej
(pronounced mAh-chay) is the Polish coloquial form of Matthias/Matthew. The Polish literary form of that name is Mateusz
I know too little about Lithuanian names but anyway, the name Mycholas (perhaps Mikolas
, Polish Mikola) seems to correspond to Nikolaus/Nicholas rather than to Michael
The corresponding Polish name for Michael
(pronounced mEE-xahl). Most probably, its Lithuanian corespondent is Michalas.
I cannot imagine the Lithuanian correspondent of Matthias/Matthew/Maciej.