Rolls-Royce has been a carmaker of choice for British royalty since the 1950s.
Another three of the eight vehicles on auction were either owned or used by members of the Windsor household, according to Bonhams.
Among them is a rare 1960 Phantom V State Limousine, which has attracted an estimate of $1.3 million to $2 million (Ksh.130million to Ksh.200million).
A collection of rare Rolls Royces, including vehicles used by Queen Elizabeth II and Princess Diana, is to be auctioned off in the UK.
The eight cars are expected to attract combined bids of up to $6.4 million (Ksh.640million) when they go under the hammer next month, according to estimates from Bonhams auction house.
Among the most anticipated lots is a 1953 Rolls Royce Phantom IV State Landaulette, used by the Queen on State occasions and kept by the British royal family for more than 40 years.
The Rolls Royce , which has a top estimate of $2.6 million (Ksh.260million), is the same model as the one used by Meghan, Duchess of Sussex, on her wedding day in May.
"There were only 18 of the Phantom IVs built, and they were bought by heads of state or dignitaries," said Bonhams' co-chairman, Malcolm Barber, in a phone interview.
Rolls Royce has been a carmaker of choice for British royalty since the 1950s.
A 1985 "Centenary" Silver Spur Saloon used by Princess Diana is expected to sell for $197,000 (Ksh.19.7million) or less.