Sir Alexander Fraser, the 8th laird of Philorth, lived from about 1536 to 1623. He transformed the small fishing village of Faithlie into the burgh of Fraserburgh in the 1590s, founded an ill-fated university, and built a castle on the headland the Gaels called the high promontory. The cost was ruinous. Fraser had to sell Philorth Castle, the family's ancestral home, to pay for it. His descendant Alexander, the 10th of Philorth, fought for the king at the Battle of Worcester in 1651. Badly wounded, he survived to live into his eighties, inheriting the title Lord Saltoun in 1669 and keeping apartments at Kinnaird Castle in later years. The last people to live in the castle were Henrietta Fraser - daughter of the 12th Lord Saltoun - and her husband John Gordon of Kinellar. After her death in 1751, the tower stood empty.

In 1787 the Trustees of the Northern Lights leased Kinnaird Castle and turned it into something else. The conversion was designed by Thomas Smith, an Edinburgh ironmonger and lampmaker who had just been appointed the first Chief Engineer to what would become the Northern Lighthouse Board. The first light at Kinnaird Head was the first lighthouse on mainland Scotland and the first anywhere in Scotland lit by the new authority. Seventeen whale-oil lamps backed by silvered parabolic reflectors - the same technology Smith had used to revolutionise Edinburgh's street lighting - made it the most powerful light of its day. Robert Stevenson, Smith's stepson and apprentice, worked on the surrounding buildings. The structure was rebuilt in the 1820s and continued in service until 1991, when a new tower took over. The old castle-lighthouse is now category A listed and houses the Museum of Scottish Lighthouses.

Fifty metres from the lighthouse stands another, stranger structure. The Wine Tower is small, three storeys tall, possibly 16th century, possibly named for a use as wine storage - or possibly from wynd, the Scots word for a narrow lane. The tower is entered through its second floor, with no door at ground level. Inside, elaborate carved stone pendants hang from the ceiling. Local tradition tells a darker story than the architecture suggests. One of the Frasers, it is said, imprisoned his daughter's young man in the sea cave below the tower and let him drown there. The young woman, learning what had happened, threw herself from the roof. Red paint on the rocks below traces where she is said to have fallen. The tower is reputed to be haunted. Whether or not any of it is true, the story has clung to the place for centuries, the way stories do at the edge of the sea.

Kinnaird Head was the first of more than two hundred lighthouses Scotland would build and maintain. Thomas Smith built nine more after it - at Mull of Kintyre, on North Ronaldsay, on Scalpay, on Pladda, on Little Cumbrae, on Muckle Skerry, at Cloch, on Inchkeith, and at Start Point on Sanday. He took on his stepson Robert Stevenson as apprentice in 1791, and when Stevenson married his step-sister Jane in 1799, the family bond was sealed. Robert Stevenson built Bell Rock. His sons Alan, David, and Thomas built more, and Thomas's son Robert Louis Stevenson eventually gave up the family business to write Treasure Island. The Stevenson dynasty would last for more than a hundred years, lighting some of the most dangerous waters in the world. It started here, on this windy corner, in a converted castle in 1787.