The Presidential Mansion (Greek: Προεδρικό Μέγαρο, romanized: Proedrikó Mégaro) in Athens, Greece, is the official residence of the president of the Hellenic Republic.

That year, King George I's son, Constantine, the heir to the throne, was born and the Greek state decided to present him with a private dwelling, when he came of age.

Twenty-one years later when Constantine married princess Sophia of Prussia, the state assigned the planning of "The Crown Prince's Palace", as the building became known, to Ernst Ziller.

After the assassination of George I in 1913 and the accession of Constantine to the throne, the Crown Prince's Palace finally became the main royal residence of the king of the Hellenes.

The only buildings appearing on the maps of the period were the manor of the Duchess of Plaisance (known as "Ilissia" and today housing the Byzantine Museum) and the Petraki Monastery, both built in country areas far from the centre of town.

In early 1870 the state allowed the sale of land to private individuals which resulted in the construction of mansions to house the wealthy families of Athens.

During modern times, with the city of Athens extending over many square miles, the Presidential Mansion is located near the centre of the capital next to the National Garden and Parliament.

It is said the King George I ordered Ziller not to make the building too pretentious, so it would blend with the other mansions on the street, and not to model it after any other palaces in Europe.

In 1962, the King commissioned architect Alexander Baltatzis to design an addition which became the largest room in the palace and is now named the Reception Hall.

The garden of the Presidential Mansion occupies an area of about 25,000 square metres (just more than 6 acres) and constitutes a green haven in the centre of Athens.

During the middle of the nineteenth century, this area, because of its especially fertile soil, was in fact the vegetable garden of the Royal Palace (now Parliament building).