Help in identifying "4 Regiment" in Polish OOB 1939

[TerryK]

In researching the war service of my deceased father-in-law it seems he was in the "4th Regiment" (source: straty.pl) and that he was captured by the Germans at Szydlow on 10th September 1939 (source: ICRC). From 1937 - 1939 he was a soldier at Drohobycz-Przemysl (source: Australian Immigration Docs).
Would someone be able to help me
(a) identify "4 Regiment" I have seen references to a 4th Legions Regiment and also a 4th Uhlans Regiment.
(b) find out what action was taking place at Szydlow in the first two weeks of September 1939 and whether a "4th Regiment" was involved, or what other units may have been there at this time.
(c) with any information on Drohobycz and whether there was an army garrison there and if so its role and function.

Any assistance would be greatly appreciated.

[Eugen Pinak]

A. None on the six "4th regiments", that existed in the Polish army in 1939, fought in the area you've mentioned.
B. No large battles were fought at this area because there were no large Polish units here. German 15th motorized corps easily fought its' way through small Polish units.
C. There was only one unit in Drohobycz - 2nd battalion of 6th Podhale Rifle Regiment, but its' other units were in Sambor, not in Przemysl.
The only idea I can come up with is, that your father was not in the regiment proper, but remained in the garrison of the 4th Legions Infantry Regiment, that was located in Kielce or was part of 154th Infantry Regiment, that was formed in the garrison of the 4th Legions Infantry Regiment on mobilization.

[TerryK]

Thank you for your reply, Eugen. That of course raises more questions. Is there any way of finding out what fighting did take place in the Szydlow area and who was involved? Assuming the information from ICRC is correct there must have been something going on there. Is it possible to access sources of information on army units, Polish or German, such as war diaries. Clearly I am new to this type of research.

[Eugen Pinak]

Thank you for your reply, Eugen. That of course raises more questions. Is there any way of finding out what fighting did take place in the Szydlow area and who was involved? Assuming the information from ICRC is correct there must have been something going on there. Is it possible to access sources of information on army units, Polish or German, such as war diaries. Clearly I am new to this type of research.

I have no idea. Maybe there was some fighting, maybe there was just rounding up of stragglers from previous battles. All I can tell, that googling gave me no info on this matter.
All I can tell, that on the German side there was probably units from 4th infantry division, and on Polish side - units from 45th reserve infantry division (of which 154th Infantry Regiment was a part).