The earliest tour which could claim to be a Lions tour occurred back in 1888.
This tour followed crickets recent trip and was when a 21-man squad travelled to Australia and New Zealand. The squad was made up of players from England, Scotland and Wales, though English players were the majority. The team was led by Robert Seddon from England until he was drowned in an accident on the Hunter river and replaced by Andrew Stoddart who later skippered England. The tour was organised by a couple of professional cricketers Alfred Shaw and Arthur Shrewsbury which is probably why the RFU did not sanction it.
The 35-match tour of Australia and New Zealand included no tests, but the side played provincial, city and academic sides, winning 27 matches, drawing 6 and losing just 2. They also played 18 games of Australian or Victorian rules football, against teams whilst in Victoria and South Australia, and won six of these, which is quite a feat.