Below is a chronological timeline showing the oldest British sheeps to the newest.

pre Roman
pre Roman

North Ronaldsay

pre Roman
pre Roman

Hebridean

Ancient
Ancient

Portland

Ancient
Ancient

Exmoor Horn

pre Middle Ages

Cotswold

Ancient
Ancient

Wiltshire Horn

5th century
pre Middle Ages

Herdwick

Middle Ages
12th century

Blackface

13th century
pre 14th century

Cheviot

Ancient
pre 17th century

Whitefaced Woodland

Early 17th Century
pre 1740

Lonk

mid 18th century
18th century

Southdown

18th century
circa 1809

Kerry Hill

1810
Early 19th century

Lleyn

Early 19th century
Early 19th century

North Country Cheviot

1830's
1840's

Wensleydale

1848
mid 19th century

Shropshire

mid 19th century
mid 19th century

Hampshire Down

19th century
19th century

Clun Forest

19th century
19th century

Greyface Dartmoor

late 19th century

Brecknock Hill Cheviot

19th - 20th century
19th - 20th century

Dalesbred

19th - 20th century
early 20th century

Castlemilk Moorit

pre 1930
1957

Llanwenog

1964
From 1964

Meatlinc

1965 onwards
Society est. 1969

Welsh Hill Speckled Face

1960 - 1980