Yoir ancestor Johannes Slick is all over the www..... depending on what you use he could have died in MA or MD.........He could be from Holland or Germany. His father could be SCHLick.., that is German.....
Seems like his birth in Rotterdam is pure conjecture.......I would be surprised if there is any basis for that...........What definitive fact do you have ??..
Frederick MD was an area were many Germans wet
CA 1725 - 1799
BIRTH: CA 1725, Rotterdam, Netherlands
DEATH: 1799, Frederick Co., MD
NATURALIZATION: 1765, Naturalized in Frederick Co.
Father: Ellius Slick SCHLICK