One obvious method of ‘persuasion’ was to dispatch a naval vessel packed to the rafters with firepower up and down the enemy coast or up an estuary in order to secure the desired political or economic concessions.
Gunboat diplomacy, they used to call it, and sport isn’t immune to similar tactics.
Rob Kearney has always possessed a howitzer of a left boot but it was an ominous verbal broadside across the bows of the IRFU that the Leinster and Ireland full-back launched at yesterday’s Irish press conference in Carton House.
Kearney didn’t quite run a French standard up one of the flagpoles outside the stately old house but he didn’t stop all that short of it in what was the first undeniable example of how Jonathan Sexton’s continental drift has changed the dynamic between the Irish union and the players.
The Louth man spoke of Sexton “testing the waters” in France, he answered questions about players needing to safeguard their own financial futures and he skirted ever so delicately around the question of where he will end up playing his club rugby the far side of summer.
French club presidents had until this week learned to ignore such stirrings when they emanated from these parts but Sexton’s switch will have alerted the Gallic sugar daddies to the fact that it is no longer simply a case of Irish players hoping the union will call their bluff.
How the world has turned. And for no-one more than Kearney.
It is just shy of two years since the British and Irish Lion signed up to a two-year deal with the IRFU whilst convalescing from a long-term knee injury picked up against New Zealand during the November internationals and which ultimately sidelined him until the following August.
He had little option at the time. He knew it and so did the union. French clubs pick and choose the best players from around the world at their leisure and a crocked Kearney risked being left on the shelf.
The union played hard ball back then because they could but the shoe will be on the other foot if the player can produce anything like his top form in the upcoming Six Nations. Do that and he will lack nothing in the way of potential suitors.
Full-backs who can catch, kick, tackle and counter-attack as Kearney can are few and far between in the world game and, in some ways, he would be even more attractive to a French club than the national team’s first-choice out-half.
Sexton has been stationed at centre now and again by Declan Kidney but he is first and last a 10, unlike the Felipe Contepomis, the Matt Giteaus and the Luke McAllisters who have offered greater versatility in their time in the Top 14.
Kearney is an option right across the back three and, though he has been playing professionally for over seven years now, he is a lightly run racehorse who played only eight games two seasons ago and just four so far this campaign.
Kearney is also a full 10 months younger than Sexton which would also allow him to spend two or three years on the continent before returning home to these shores and collect the attractive tax break for sportspeople who finish their careers in Ireland.
No doubt about it, the balance of power has shifted.