Finding the perfect travelling companion isn’t always easy, but Fiona has similar interests, and we’ve been friends for 40 years. An author and artist, she lives in Glasgow, while I’m in London and Fife, so I don’t see her nearly as much as I’d like. We plan to sketch the towns and cities along our journey.

It’s Sunday morning, the sky is azure blue, swans glide by and church bells peel as our river cruise ship, Viking Sigrun, glides down the Middle Rhine. Charismatic cruise director, Marian Fatsik provides commentary while 28 fairytale castles atop hillsides give a glimpse into bygone times. It’s breathtakingly beautiful.

At Rudesheim we disembark to enjoy the well-preserved Marksburg Castle. We pass the Lorelei Rock as the eerie melody of the mermaid plays over the Tannoy. We’re in wine country and manicured vineyards cling to steep inclines.

The Romans recognised that the soil and micro-climate were favourable for grape cultivation and Riesling is the most widespread variety. At dinner we enjoy crisp, dry wines, and the wine list is an oenophile’s dream. Koblenz is a medieval town, which boasts a cable car ride over the river to the historic Ehrenbreitstein Fortress.

The old town has a pretty square where we order coffees and sketch until it’s time to return to Viking Sigrun for dinner and a concert by The Koblenz String Quartet. Culturally and historically the Rhine is one of the greatest rivers in Europe. No other river has so many illustrious cities .