The will of Nicholas Query of Montgomery County, MD was written 13 Oct 1788 and proved 15 Dec 1788. He mentioned two sons: Daniel and Henry. And he named their five sisters: Mary Ann March, Christine Schindler, Catherine March, Elizabeth Humbert and Susannah Tice.

Catherine was of course the wife of Philip Mertz so I would assume the husband of Mary Ann also was named Mertz.

Another assumption would be, as is often the case, that brothers married sisters - and therefore that Mary Ann’s husband was Philip’s brother.

I believe I know the names of the wives of most of Philip’s brothers and think the two I am least confident about are George and Heinrich. (Another son was named George Heinrich, but I know his story as well, so he is not be confused with George or Heinrich.)

A lot of people on Ancestry say that the wife of George of early Frederick County, MD was Mary Ann Query. But I think he may have married Catherine Hahn. I really could argue in favor of either theory.

The records of Mertz Church show that for several baptisms in the 1770’s, the sponsors were Heinrich Mertz and Ana Maria Quieren. I have often observed that two single sponsors often later married.