They were also the first Lions squad to tour Australia on its own, with the 1888 Lions having visited Australia and New Zealand on one tour. It would be 90 years before another Lions squad would pay Australia the same compliment.
The Lions played 21 games on tour, including four Test matches, with the matches spread over nine-and-a-half weeks.
Australia came out on top in the first-ever Test between the two sides, comfortably winning 13-3, but the Lions hit back to claim a series victory.
The tourists won the next three Tests on the trot, comprehensively defeating their hosts in the second and fourth encounters in Brisbane and Sydney and winning the third by a single point.
They were, until Sir Ian McGeechan's 1989 Lions, the only British and Irish tourists to win a Test series after losing the first rubber.
The biggest win of the tour came in the Lions' final match before heading home, with the tourists beating Victoria 30-0 in Melbourne - just the second time the Lions had reached 30 points in 97 games.
A little bit of history
In the year that the Lions left for Australia, Queen Victoria was into her penultimate year on the throne; William McKinley was the President of the USA, the Second Boer War began; Alfred Hitchcock, Al Capone and Fred Astaire all entered the world; composer Edward Elgar published the Enigma Variations, the tape recorder, the lawn mower and Aspirin were all patented; the foundations for the Victoria and Albert Museum were laid; Robert Scott began his ill-fated expedition to the Antarctic and the cricketer WG Grace played his final Test match.
The Lions arrived in Australia eight years after the first attempt at a federal constitution was drafted; five years after Waltzing Matilda was first sung in public and in the same year that the decision was made for the country's capital to be in the state of New South Wales, but not within 100 miles of Sydney.
Did you know?
The Reverend Matthew Mullineux captained and managed the 1899 Lions but nobly stood down as skipper for the final three Tests following defeat in the first.
Mullineux remains the only Lions skipper not to have represented one of the four Home Unions.
A veteran of the 1896 tour to South Africa, Mullineux returned to that country after his second Lions adventure to act as a chaplain during the Second Boer War.
He would later win a Military Cross fighting the Germans in France while serving during the First World War.
Mullineux wrote to the leading newspapers in Australia detailing the make up of the Lions squad prior to the start of the tour in a bid to ensure the games were as well publicised as possible.
The tour manager gave brief descriptions of the capabilities and strengths of individual squad members in a move that seems completely alien to the modern-day game in which the players are world renowned stars.
Gwyn Nicholls was the standout player on tour; a Gloucestershire native who played for Cardiff and Wales and was regarded by the Welsh as the finest three-quarter of his era.
Nicholls played in all bar two of the tour matches, scoring 11 tries and setting up many more.
Although still nowhere near the make up of modern-day Lions squads, the 1899 Lions included more capped internationals than the first side to visit Australia 11 years earlier.
There were a total of seven players who had already represented their countries in the party - two English, two Irish, two Scottish and one Welsh.
The squad was made up of 21 players - the same number as had toured Australia in 1888. But whereas the split on the first tour had been nine backs and 12 forwards, this time the party was made up of 10 backs and 11 forwards.
E Martelli Dublin University
CEK Thompson Lancashire
AM Bucher Edinburgh Academicals and Scotland
GP Doran Landsdowne and Ireland
EG Nicholls Cardiff and Wales
ET Nicholson Birkenhead Park
AB Timms Edinburgh University and Scotland
CY Adamson Durham
G Cookson Manchester
MM Mullineux Blackheath (captain)
A Ayre-Smith Guy's Hospital
FC Belson Bath
GV Evers Moseley
JS Francombe Manchester
GR Gibson Northern and England
HGS Gray Scottish trialist
JW Jarman Bristol
W Judkins Coventry
TMW McGown North of Ireland and Ireland
FM Stout Gloucester and England
BI Swannell Northampton
To view the full list of fixtures and results from the 1899 tour, simply click here