The curtain may well have come down on 400 years of papal history with the opening to the public of the Apostolic palace of Castel Gandolfo, the pope’s summer residence in the Castelli Romani south of Rome.

It is not that the Holy See has opted to sell off this splendid 17th-century palace, overlooking Castel Gandolfo lake and just up the road from the wine town of Frascati. No, the decision to open it to the public is linked to the fact that the current landlord, Pope Francis, never uses the place.

Apostolic palaces do not come high on Pope Francis's list of desirable residences. Famously, as all the world now knows, he has chosen to live in the Domus Santa Marta, a glorified Vatican bed and breakfast, rather than the Vatican's apostolic palace.

If he has no use for an apostolic palace on his doorstep, he has even less time for one 25km south of Rome. Hence the decision to open it to the public – and the speculation as to whether any future pope will want to reclaim the place and live in it, even for a few summer months.

Whatever about future popes, tourists are certain to greet the opening of this never previously visited jewel. Opening the palace for a press viewing on Friday morning, the director of the Vatican Museums, Antonio Paolucci, suggested that the best thing about this famous building was its location.

“Whoever enters the great front door of the Apostolic Palace of Castel Gandolfo enters into a world of pure beauty. When you step out on to the terrace, you see not only the blue lake below you, but also the hills on the other side, covered by woodlands that remains intact and untouched . . . Walking through the rooms of the apostolic apartment, you can hear the murmur of history. Take your time, do not rush through.”

On the walk through, it occurs that it is just as well that this place was conceived as a summer residence, since it has a distinctly cool, marble and imposing feel to it. For all that, the palace in Castel Gandolfo is certain to prove a major tourist attraction.

When else, before now, could you wander through a pope’s house, inspect many of his clothes (most of them hundreds of years old), look at wax reproductions of his courtiers, walk around his bedroom, view his most imposing furniture (the sort they used to carry him around in) and, above all, enjoy the wonderful panoramic views out over the lake?

Among all the historical artefacts, perhaps one of the most surprising concerns a number of black-and-white photographs recalling life in the palace during the second World War, when 1,600 homeless people were housed in the grounds and the palace itself.

These pictures show people arriving up at the palace with donkey-powered little carts, piled high with their belongings. Life for these refugees seems to have been much improvised in camp style, tented villages around the gardens.

One interesting feature of the palace tour is that during the war years, Pope Pius XII had to regularly clear out and give up his bed to women about to give birth. In those days, when decent beds were scarce, the pope's bedroom remarkably used to double up as a maternity ward.

When Pope Francis first made it clear that he no intention of using Castel Gandolfo, the decision had a dramatically negative effect on the little town’s economy. I Castel Gandolfo he is the major attraction and, without his guaranteed regular presence, bars, restaurants and shops all suffered.

Not that this was a new experience, given that only 15 of 33 popes in the last four centuries have actually used Castel Gandolfo. However, the locals (and the tourists) now both have reason to look forward to a future of better days.

The palace will be open to the public, 9am-1pm on Monday to Fridays and 9am-4.30pm on Saturdays.