The things differed a lot between civilizations, status of slaves and the rewards promised for going to war.
First of all, there was no single, the same notion of "slavery" throughout history.
What in Muslim world is translated as "slave" could have a different meaning at the time and place where it was used. For instance, one could ...
The french 75mm field gun (Canon de 75 modèle 1897, which came out in WWI) and was still available in large numbers in 1940 ?
Which was used by France, Poland, Great Britain and the US 1940.
In the case of the US, the carriage was changed into a split trail design.
The inter service rivalry in the Japanese military did exist, but examples of how that degraded fighting ability are not that prominent.
The IJN made a notable effort to reinforce the IJA on Guadalcanal, and lost a lot of ships, and especially lost a lot of trained naval aviators that they couldn't quickly replace. During the battles around Guadalcanal, most ...
No and probably no.
The industrial potential of Japan and the US was so disparate that Japan couldn't have won. Better coordination might have gained them a few months, which might have stretched things into 1946. Or not. Look at these numbers for aircraft production, for instance.
A much better strategic decisionmaking culture might have caused them not to ...
There is a version of this picture that bears the description:
Right Hon. Sir Redvers Buller, V.C., G.C.B., etc.
Commanding in Natal
In the Uniform of Colonel Commandant, King's Royal Rifle Corps
Searching just for the uniform of that unit then lists Buller as a prominent 'search-hit', like Original Rifle CORPS Uniform Pics, and reveals this illustration:
More than you can imagine, and not only minor kingdoms.
The main actors of WWII where still using WWI equipment, specially at the beginning.
From the navy standpoint, many main unit where still from WWI (all Queen Elizabeth-class and Revenge-class, for example, for UK) for all the participant.
From infantry, lot of equipment was from WWI, here few examples:
Why limit yourself to WW1? The Dutch army went to battle in 1940 with (some) equipment predating the Franco-Prussian war.
Dutch equipment WW2
I think the question is mood. Why? Because the age of a weapon is not that important. Look at the time period: 1914-1940 = 26 years.
Many advanced weapons systems in common use today are much older:
The last time the United States Congress issued a letter of Marque and Reprisal was during the War of 1812. The last time they considered it was during Andrew Jackson's administration. The Declaration of Paris is an international law signed onto by over fifty nations. Created in 1856, the United States abides by the provisions thereto. It prohibits the act ...