Events are planned along the route by the riders to raise money
Seven horse riders in period costume are aiming to retrace the route taken by Henry Tudor more than 500 years ago from Pembrokeshire to Leicestershire.
On Sunday they started the journey taken by Henry Tudor which culminated in the defeat of Richard III at the Battle of Bosworth in 1485.
Setting off from Dale near Milford Haven, the riders plan to take six days to travel more than 100 miles.
The Henry Tudor Ride aims to raise over £50,000 for the Army Benevolent Fund.
"On the first day they will pass through Brunt Farm, south of Dale where Henry Tudor passed before going north towards Haverfordwest," said one of the organisers, Lt Col Charlie Nutting.
The riders will include Major General Sir Evelyn Webb-Carter, controller of the charity and the military historian Professor Richard Holmes.
Prof Holmes described Bosworth as one of the "great decisive battles in English history".
"You've got two really strong personalities - Henry Tudor - who became Henry VII - and Richard III and a lot of people identified with one side or the other," he added.
"If you're Welsh you're quite likely to sympathise with Henry Tudor."
The riders will also pass close to Cardigan, Welshpool, Shrewsbury and Cannock Chase before arriving at the battlefield.
The Battle of Bosworth ushered in the Tudor dynasty
Henry VII's paternal grandfather, Owen Tudor, a Welshman, is said to have secretly married the widow of Henry V, Catherine of Valois, and the result of their union was the father of Henry VII.
However, Henry's claim to the throne derived from his mother, Lady Margaret Beaufort.
After his victory he married Richard III's niece, Elizabeth, joining the Houses of York and Lancaster together and eventually bringing the civil wars to an end.
Events are planned along the route, culminating in the arrival of the party at Bosworth Field in Leicestershire on Saturday, 19 July. To celebrate their arrival in Bosworth Field, Prof Holmes will give a battlefield tour the following day.
All the money raised from the event will go towards supporting injured soldiers or families of those killed during service in Iraq and Afghanistan.
In 2005 a similar horseback event from Liverpool to Marston Moor, retracing the ride of Prince Rupert, raised over £45,000 for the fund.
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