A botanist researching ancient oak trees in Britain has unexpectedly discovered the largest collection of the ancient oaks in all of Europe, according to The Daily Mail.

The collection includes as many as 60 trees, dating back nearly 1000 years. Four of them are huge—measuring 9 meters in circumference—while one is standing dead. The oaks are located on the 120-acre grounds of Blenheim Palace in Oxfordshire, an estate once occupied by Winston Churchill. The area of wilderness is known as High Park and was originally conceived as hunting grounds by King Henry I in the 12th century. Later, landscape architect Capability Brown preserved it when designing the estate, which is now a UNESCO World Heritage Site.

Aljos Farjon, a research associate at the Royal Botanical Gardens in Kew, was doing fieldwork for an upcoming book when he found the medieval trees. The site is one of around 100 that Farjon has visited in his research.

He told The Daily Mail, “There is not really anything like this in Europe. There are 22 sites of great importance in England and Blenheim Palace is right at the top of this.”

For more, including images of the ancient oaks, check out the video below.

[h/t The Daily Mail]