The history of the Carlton complex reaches back as far as the 13th century. In this period the tavern "U Labute" (At the Swan) stood on its site and later, from 1760, the travellers’ inn "U troch zelených stromov" (At the Three Green Trees) stood along its right-hand side. This offered guests not only accommodation but also stabling for their horses. It took its name from the broad green trees growing in its courtyard, and in this period it ranked among the most celebrated inns in the whole country. In 1838 Johann Löwy, the director of the first Hungarian Bratislava-Trnava railway line, bought the building and had it converted on the design of builder Ignác Feigler, Jr. Thus, from the original single-storey building the modern three-storey “U zeleného stromu” (At the Green Tree) hotel originated in 1844 to 1846, whose guests praised not only the comfortable rooms but also its advantageous location on the banks of the Danube.

From 1860 the hotel “U zeleného stromu” faced competition from the adjacent hotel “National”, which was located on Mostova ulica (Bridge Street) and offered its guests 27 rooms. The National was established by the Speneder family in 1860 and later converted on the design of architect Ignác Feigler. The hotel was changed into a varied, grandiose building with facades on Mostova ulica and on Hviezdoslavovo námestie. The well-known “Savoy” coffeehouse, located on the hotel’s ground floor, was a part of the building.