I agree with Norman on all counts, but would add that the apostrophe in "1900's" is unnecessary. The apostrophe is used in making plurals where the meaning would otherwise be unclear. Example: "How many a's are there in "language"?" would be unclear without the apostrophe. There is no such uncertainty in "1900s", so it's not needed.

Hi Durk, in the 1900's in the early 19th century in early 1900