GIVEN the importance they attached to the Sun, Moon and stars, the Neolithic residents of Skara Brae may have viewed Yuri Gagarin as a god.
The Russian cosmonaut secured his place in history when he became the first man in space on 12 April, 1961, orbiting the Earth in the spaceship Vostok 1.
The anniversary of the defining moment in the space race will be marked today, thousands of miles from Gagarin's home in Moscow, in a ceremony on Orkney. His great feat will be added to a timeline of world events which have taken place in the 5,000 years since Skara Brae was inhabited.
The pathway to the Skara Brae prehistoric village is lined with 13 carved stones that form a time trail of milestones in human history. It was created by Historic Scotland to emphasise the immensity of the changes that have taken place since the settlement was inhabited.
The 14th stone, about 20cm by 30cm and engraved by Leslie Merriman, a member of Historic Scotland's Orkney Monument Conservation Unit, will read simply: "1961, first man in space."
The idea for its inclusion came from Alexander Korobko who visited the islands in 2006 in search of his Orcadian roots. Mr Korobko and a number of Russian dignitaries, as well as cosmonaut Georgi Michailovich Grechko, will attend today's unveiling, which is being filmed for Russian television.
Mr Korobko said: "I am delighted that Historic Scotland is commemorating the space flight of Uri Gagarin at Skara Brae."
Doreen Grove, Historic Scotland's head of access and understanding, said Gagarin's mission was a defining moment in human history: "By sending the first man into space, the Russians heralded the dawn of a new age. The timeline will help underline just how much has changed since the days of the Neolithic farmers who built Skara Brae."
Tatiana Danilova, trade marketing executive at VisitScotland for central and eastern Europe, added: "Russia is an important emerging tourism market for Scotland. I hope that the stone will be something Russian visitors enjoy seeing."
Skara Brae, which is part of a UNESCO World Heritage Site, was inhabited between 3200 and 2200BC and is the best preserved prehistoric village in northern Europe.
The site was exposed by a storm in 1850 and excavations revealed a series of dwellings, separated by passages, with stone beds, dressers, seats and boxes for provisions, and a hearth where dried heather, bracken or seaweed was burned.
The Sun and Moon were important to the residents, who aligned major monuments to sunrises and sunsets.