Antique Oil Painting - $5 turned into $5000

[Gold Maven]

I know very little about art, but I wonder if the artist abbreviated his signature because of the small 11x7 format.

gl, hope you get a good price.

 

[gino22]

I know very little about art, but I wonder if the artist abbreviated his signature because of the small 11x7 format.

gl, hope you get a good price.

He liked to use his full name in block capitals even on the small works:
Martin Monnickendam (1874-1943) - 150-199 Martin Monnickendam 1874-1943 | ACA Auctions

This concerns me, since the "M" on the OP's painting isn't nearly as stylized as the "M's" in all of the signatures I've been able to come across online. Monnickendam's M's resemble hearts or upside down triangles, very Art Nouveau. The cursive writing on the back is probably from another source, likely a gallery.

Looking over his other work in detail, this painting seems restrained by comparison. Could just be the picture quality, but I am seeing a very conventional religious portrait. Monnickendam's famous works depicting a Synagogue are densely populated and quite lively, not focusing on any particular subject. Like most artists, he has done conventional portraits and landscapes, but the ones I am coming across still have that Impressionist flourish, conveying lots of movement and variance in light.

OP, can you post some detailed pics so we can see the brushstrokes, etc?

Someone else could have put the Jewish subject together with the "M" and incorrectly (or deceptively) attributed it to Monnickendam. Could still be an early work by the artist. But I wouldn't attribute it to him until consulting an expert, or finding evidence that he ever used that "M." signature.