It is strange what details remain with one after time spent in a museum. You look at paintings differently each time you see them, perhaps one of those lovely bonuses in life. I thought about this again as I was re-reading a diary about my last visit to the Prado Museum in Madrid.

I was in rooms filled with 17th century Spanish portraits of royalty. The opulence of their attire is dazzling, almost overwhelming in some cases, and the eye has difficulty focussing on all the details. Jewels, fabrics, head dresses, so much wealth and power displayed. However, this particular day, I began to get intrigued by the different methods, so exquisitely painted, of fastening these elaborate dresses of brocades and silks.

This was no case of stepping into your robe and zipping it up as we now do so unthinkingly. In the first place, these royal ladies had help, serious help, from their maids, even to get into the robes. Arranging the dress was clearly complicated. When it then came to fastening the long, heavy robe, this was indeed another affair.

This was the first painting that stopped me in my tracks. Look at all those bows, stuffed into their scissor-like sheaths, down the front of the dress. That is rhythm and class, regal style!

Evidently Margaret of Austria liked this sort of dress fastening, as the previous year, Pantoja de la Cruz had already painted her portrait with a similarly adorned dress, where these complex fastenings became the focal point against the relatively subtle and sumptuous fabric of the dress.

This fashion of bows tucked into sheaths had evidently been the ne plus ultra of fashion in the Spanish court for a number of years, because I found more portraits with variations on this theme. This earlier portrait showed the knotted bows arrayed vertically, not diagonally

The Infanta Clara Eugenia evidently liked variety in her fastenings and design of robe. In this other portrait, she had the circular gold medallions not only as fastenings but also as part of the decorative V falling from her shoulders.. The weight of these gowns must have been substantial.

The next portrait that caught my attention was so complex in the way the dress was fastened that I actually drew it in my drawing book, simply to work out the intricacy of its design. Complex knots swirled to a central gold and ruby jewelled oval, topped off with pearls. Marvellous!

I began to be almost dizzy with these regal ladies staring down at me from their canvases, each with their robe fastenings helping to make a clarion declaration of pomp and power.

With such arresting jewels and adornment above her waist, this Empress opted for different fasteners down her dress, the perfect complement to everything else which was shown off to such good effect on the black sobriety of fabric. The squared gold clip-together buckles were discreetly elaborate and effective, pacing themselves down the centre of her robe to the hem.

In all of these robes, however, the fastening was a huge part of the overall design, not like our dresses today. Now, zips are mostly discreet affairs, hidden behind plackets, efficient and utilitarian.

Here Doña Catalina was far more splendid, despite the more predictable gold ball buttons above. That belt buckle was intended to send messages of power, wealth, taste, position and individuality!

One other portrait served, in a way, to underline the opulence of the other ladies’ robes and fastenings. Joanna of Austria (1535-73) was the daughter of Emperor Charles V, and sister of King Philip II of Spain. After marrying the Portuguese prince, John Manuel. who died in January 1554, days before Joanna gave birth to their son, Sebastian, (later King of Portugal), she eventually entered the Jesuit Order. She later founded The Order of St. Clare. This portrait dates from 1560; she kept it for herself until she died in 1573. Joanna of Austria had concerns other than status and adornment; her dress was quietly opulent but fastened oh so discreetly.

That hour of fascination in the Prado made me look far more closely at the ways ladies fasten their clothes. Art is not only marvellous historical testimony and instruction: it makes one look harder at everyday things around us now.