There were British, French & Italian Somalilands on the empire's maps (most circulated maps back then).
https://upload.wikimedia.org/wikipedia/ ... ia1911.png (larger map)
On Italian maps, it used to be Somalia Britannica, Somalia Francese & Somalia Italiana.
The story behind those names & borders began in a room in Berlin, which formalized the scramble for Africa:
The answer is, neither is older. The Brits & Italians were in that room when Africa was partitioned, and each got a piece of the cake according to their status (Britain being an empire, got a large piece).