The Palau Reial Major lies between Plaça del Rei and Carrer dels Comtes in the heart of the Barri Gòtic and is a collection of buildings that comprised the residence of the Counts of Barcelona and Kings of Aragón.
Two of the main buildings - the Saló del Tinell, which was the Royal reception hall, and the Chapel of Santa Àgata are part of the MUHBA Barcelona History Museum so you have to buy a ticket if want to see inside.
If you visit MUHBA, apart from the impressive Roman excavations, you can also see the ground floor of an earlier Palau Comtal, which dates from the 10th century and there is evidence that there has been a palace on the site of the Palau Reial Major since the Visigoth King Ataülf brought his court to Barcelona in the 5th century AD.
However, apart from the steps leading to the Saló del Tinell, most of what we can see today dates from the early 14th century onwards.
As you walk into Plaça del Rei, you see the Saló del Tinell ahead of you with the Mirador del Rei Martí above it.
The Chapel of Santa Àgata is to your right with the Palau del Lloctinent facing it to your left.
The steps that lead up to the main entrance are one of the oldest parts of the Palau Reial Major and date from the 11th century.
This was where the Consell de Cent - Barcelona's proto-democratic Council of One Hundred - met before it had its own hall in the Casa de la Ciutat.
In 1228, Jaume I the Conqueror assembled the Corts here to ask for permission to invade Mallorca and more importantly to agree on the division of booty should the venture be successful.
On 7 December 1492, the Catalan farmer Joan Canyamars tried to murder Ferdinand the Catholic but ended up just stabbing him in the neck with his sword.
Canyamars was condemned to 'a very cruel death as an example and punishment to others'.
Although, owing to the assassination attempt, the Catholic Kings received Christopher Columbus at the Monastery of Sant Jeroni de la Murtra in Badalona on his return from the Americas in 1492, an official reception did take place here in the Palau Reial Major a few days later.
The steps lead up to the entrance to the Saló del Tinell on the left and the Capella de Santa Àgata on the right.
However, as both are part of MUHBA, you can only enter from inside the museum.
The right hand door is the Gothic entrance to the Chapel of Santa Àgata, which was started in 1302 by Jaume II the Just.
Incidentally, Saint Agatha is a popular Sicilian saint and it's no coincidence that Jaume the Just had been King of Sicily prior to becoming Count of Barcelona and King of Aragón.
The chapel is set in the Roman Wall and the sacristy, above which the tower rises, is actually inside one of the Roman defence towers.
To the left of the steps runs the facade of the Saló del Tinell, which was the main ceremonial hall of the Counts of Barcelona.
Although the interior of Saló del Tinell was built by Pere the Ceremonious between 1359 and 1570 and is Gothic, the triphora windows on the first floor date from an earlier period and are Romanesque.
The rose windows above are later and were probably added at the same time as the interior was completed.
At the far end of the facade, look out for a very early crest of the Generalitat de Catalunya.
The Mirador del Rei Martí - the Watchtower of King Martin - sits above the Saló del Tinell overlooking the Palau del Lloctinent and was erected in 1555.
The name of the tower refers to Martin the Humane, the last of the Catalan Counts of Barcelona, who died in 1410 so the current mirador obviously had nothing to do with him.
The truth is this veritable medieval skyscraper occupies the site of an earlier tower that gave King Martin a view of the sea.
The building we see today, though, was a watchtower used by the Spanish viceroys to control the always rebellious people of Barcelona.
Following the line of the facade round to your left, you come to the Palau del Lloctinent.
The palace, which was built between 1549 and 1557, was originally intended as a royal residence but this was a time of absentee kings and it became home to the king's dreaded representative, the viceroy.
Lloctinent means viceroy in Catalan.
On the ground floor, the palace has a very pleasant patio with a fine balcony above.
The Palau del Lloctinent now houses the Archive of the Crown of Aragón.
If you walk through the Palau del Lloctinent onto Carrer dels Comtes and turn right, you come to Plaça de Sant Iu.
Opposite the impressive side door of Barcelona Cathedral, you'll see part of the back wall of Saló del Tinell, which looks Neogothic rather than original to me.
If you walk through the door marked Museu Frederic Marès in Plaça de Sant Iu, you'll come to El Verger.
This was the courtyard and patio to the Palau Reial Major and although most of it was reconstructed in the early 20th century, you can still see part of the Romanesque facade of Saló del Tinell.
El Verger is particularly pleasant in summer and is a perfect place to take a brief respite.