Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
gwerzhañ
←
Welsh
gwerthu
(cognate)
←
Cornish
gwertha
(cognate)
←
Old Breton
*gwerthaff
(inherited)
←
Middle Breton
guerzaff
(mention)
→
Welsh
gwerthu
(cognate)