Nikola Tesla (1856-1943) in his laboratory in Colorad Springs in 1899, with the book
Theoria Philosophiae naturalis by  Ruđer Bošković, a famous Croatian scientist from the 18th century..

Nikola Tesla

Summary. Nikola Tesla (1856-1943) attended the high-school (High Real School) in Rakovac, Croatia, in the period of 1870-73, where the subjects were taught in German language. One of the compulsorly subjects that young Tesla had, was Croatian language (Kroatische Sprache), which was his mother tongue. Martin Sekulić, high school professor of Mathematics and Physics, was probably the most important among Tesla's professors during his entire education, since he enthused him for electricity, magnetism and polar light. Sekulić was an active researcher and a member of the Academy of Sciences in Croatia's capital Zagreb, in the Department of Mathematics and Natural  Sciences.

Martin Sekulić (1833-1905), professor of Mathematics and Physics in Rakovac (now a part of the city of Karlovac),
in Croatia, in the High Real School which Nikola Tesla attended in the years 1870-1873.
Sekulić is probably the most important professor during entire schooling of Nikola Tesla.
His experiments enthused young Tesla for electricity and magnetism.
Martin Sekulić was an active researcher and a member of the Academy of Sciences in Croatia's capital Zagreb,
in the Department of Mathematics and Natural Sciences.
The working language in the High Real School (Obere Realschule) in Rakovac was German.
Rakovac was then a part of the Croatian Miliatry Frontier,
 i.e., (according to the then terminology) of  Kroatischen Militär-Grenze, or Hrvatska krajina, or Hrvatska Vojna krajina.
Later, the name of Hrvatsko-slavonska Vojna krajina was also used.

Some of the compulsorly subjects that young Nikola Tesla listened to as a student of the VI'th grade (roughly, age of 16)
are shown below. The source is the  yearbook of the Rakovac High Real School for the period of  1872-1874.

Croatian language

Mathematics

Physics

These subjects had been described not only in German, but in Croatian langauge as well:

Hrvatski jezik - Croatian language

Mathematics

Physics

Here we stress that Croatian language was the mother tongue of young Nikola Tesla. This fact is missing
in literally all biographical sources (including monographs) dealing with Nikola Tesla.
However, it is a well documented fact by available school yeabooks from the period of 1870-1873, that we cite here.

We conclude with the (duplicate of the) matriculation form that young Nikola Tesla earned
in Rakovac, Croatia, in 1873, at the age of 17:

The title page of the (duplicate of) Nikola Tesla's matriculation form, issued in Croatia's capital Zagreb in 1885.

As we can see (in the second last line), one of the subjects
of Nikola Tesla's final exam was Croatian language.
Please, see a more detiled information.

Croatian translation of the matriculation exam of Nikola Tesla kept in the Karlovac Gymnasium in Croatia,
containing the names of the members of the exam committee.
The first column at the bottom contains the names of the subjects at the exam,
while the second column has the corresponding marks obtained.
In the third line of the table at the bottom, Nikola Tesla's Materinji jezik (i.e., Mother tongue)
is indicated as hrvatski (i.e., as Croatian language).
The fourth column of the second last table indicated without any doubt Hrvatska (i.e., Croatia)
as his DOMOVINA (i.e., as his homeland).
His birthday is indicated as the 2nd November 1856,
which is a mistake: the correct date of his birth is 10th July 1856.

Nikola Tesla godine 1933.


In 1941 Nikola Tesla invited to lunch with him in New York a famous Croatian-American boxer Fritzie Zivich,
known under the pseudonym The Croat Comet (as well as his brothers, who were also boxers),
after his successful defense of the world title in welter-weight category.
Source  newsinteractive.post-gazette.com.
From left to right: Joe Zivic, Fritzie Zivic, Nikola Tesla, Jack Zivic, Pete Zivic and Eddie Zivic.

The Croat Comet Fritzie Zivich (originally Živčić) and Nikola Tesla

Fritzie Zivic was inducted to the International Boxing Hall of Fame in 1993.

Nikola Tesla, USA ship of the Liberty series, built in Baltimore in 1943 on the occasion of the death of Nikola Tesla.
Photo by the courtesy of Vladimir Novak, Croatia / USA

Ships for Victory