Fleet. In the wars for national unification (1912–1918), graduates of the Training Unit participated in the mine laying and mine sweeping operations, the attack against the Ottoman cruiser Hamidiye, the Assault operations in Balchik, Kavarna and Kaliakra, the Engagement of Balchik on December 13, 1916. They had the honour of mastering the new naval equipment: seaplanes and the first Bulgarian submarine. This was the period when French, and then German language studies were introduced and as a result, some of the graduates of the Engineering School to His Majesty's Fleet were selected to become naval officers and sent for training at the Academia Navale in Livorno (Italy – 1914), and later at the Marineschule Mürwik (Germany – 1916–1918). Changes occurred in the Engineering School also. In 1917, after a short training course for a select group of graduates of the naval Alma mater, the first officer class graduated. In 1918, the school received the building of the present-day Aquarium in the Sea Garden, where it remained until 1922. After the wars for national unification, the maritime education system underwent another reorganization. The Training Unit was now called the Maritime Training Unit and for the first time it was in charge of all educational structures from which most modern faculties, departments and colleges of the Nikola Vaptsarov Naval Academy originate. The establishment of the present name In the period 1919–1920, the officer training course was not only successfully conducted but also the first graduates, pursuant to Decree of the Council of Ministers No. 6/ June 1, 1920, were issued a certificate for completed higher specialized naval education "following the full curriculum of the Maritime Corps in St. Petersburg". Diplomas of higher education were also issued to the participants in the preceding courses. Later the curriculum of this structure was significantly improved. In 1925 and 1928, based on the accumulated experience, two Shipmaster courses were formed, after taking which the trainees, after many years of theoretical and practical training, were issued diplomas for completed higher specialized naval education. Later some of them became prominent members of the Maritime Police Service (the official title under which the Bulgarian Navy existed under the terms of the Treaty of Neuilly-sur-Seine) and "master mariners" at the Bulgarian Commercial Shipping Company (the predecessor of Navigation Maritime Bulgare LTD) Under the terms of the peace treaty of Neuilly-sur-Seine, in the spring of 1921, His Majesty's navy was disbanded.