Prvog Ratnog Prvenstva Zagreba- 1918

A poster for 2 matches in a Zagreb championship tournament. The game  played on 19th May 1918 was between  Hrvatski akademski športski klub (HAŠK) and ŠK Zagreb. The following day FC Sparta Elektra would play HŠK Građanski.
Six clubs took part in this league and the final standings were as follows:

1. HAŠK
2. Građanski 
3. AŠK Croatia
4.ŠK Zagreb
5. Sparta Elektra 
6. HŠK Slavija Zagreb

Croatia- early days...

Up until the foundation of The Kingdom of Yugoslavia in 1918 Croatia was a part of the Austro-Hungarian Empire. 
Football was introduced to Croatia in 1873 by a group of Englishmen who came to work on building a new factory in Rijeka.
 Sailors of the Royal Navy played a game in Croatia in 1887, but interest among the locals was not great. 
In 1903 Prvi nogometni i športski klub Zagreb, (First Football And Sport Club Zagreb- known by the acronym PNIŠK) was founded. 
In 1904 the football section of Hrvatski akademski športski klub (Croatian Academic Sport Club-HAŠK) came into being. 
In 1905 PNIŠK played Ferencvárosi Torna Club in Budapest, losing 11-1.
 PNIŠK and HAŠK  played each other for the first time on 26th October 1906 at Zagreb. 800 spectators watched a 1-1 draw. This is considered the first official game between two Croatian sides and gave rise to the foundation of many new clubs.

PNIŠK / HAŠK (light tops) Slavia Prague (halved tops)

On 23rd and 26th June 1907 a combined PNIŠK / HAŠK team played two matches in Prague against Slavia Prague. 

Slavia won both games;15-0 and 20-0.