But now the inseparable pair are breaking up, in a move that is rocking the Spanish financial world and thrilling those who have followed their Technicolor career for more than a decade. Hand in hand, the sisters saw a cement business inherited in 1966 from their Polish refugee father become a conglomerate that built roads and reservoirs throughout Spain. The company, Fomento de Construcciones y Contratas (FCC), is the flagship of their joint fortune, estimated at $2.2bn (pounds 1.3bn), among the world's top 200.
Through skilful diversification steered by the two, and shrewd international deals (from building motorways in Canada to cleaning Brighton beach), the company rode the recession and prospered. But Alicia, 45, blond and beautiful, has announced that she is fed up with business and wants to quit.
In perhaps the last twist of a saga that has enthralled Spaniards, banking wizards are disentangling the joint empire in which each owns 28.26 per cent. Esther, 47, wants to continue running the show and is imposing stiff conditions on buyers of her sister's share. Observers, scenting a likely pounds 83m tax bill, reckon that if each takes her separate path the company may have to break up.
None of this would amount to more than a ripple in the financial press were it not for the fact that these two discreet and brilliant women have challenged every stereotype. Orphaned when their father, Ernesto, fell from his horse in 1962, both married young - at 18 and 20 - to two cousins, both called Alberto. The so-called "two Albertos" took over the running of FCC in the 1970s and the sisters kept in the background as dutiful wives and mothers.
By the late 1980s the company had prospered and the Albertos became powerful industrialists. But in 1988, Alicia was shattered to discover that her Alberto (Cortina) was carrying on with a marquesa, Marta Chavarri. Shortly afterwards, Esther found that her Alberto (Alcocer) was seeing a former model, Margarita Hernandez, secretary to Javier de la Rosa, head of the Spanish branch of of the Kuwait Information Office.
Each sister divorced her husband - simultaneously, naturally - and on International Women's Day, 8 March 1990, they took over the running of FCC. The two Albertos slunk from the 42-storey company headquarters in the heart of Madrid, each pocketing pounds 2.7m, a fraction of what they claimed.
Esther and Alicia emerged from seclusion to supervise directors' meetings of Spain's top construction company, in a no-nonsense style, with their trademark elegant suits, smart ear-rings and decolletages. They operated as one, but it is now said that Alicia never took to business with quite the relish of her sister.
No one really knows why they have parted company, but problems about the succession are thought to be at stake. It should come as no surprise that each sister has three children - Esther has daughters and Alicia has sons - and that the eldest of each are the same age, 26. Esther Jr works in the company and is shaping up as a possible successor to her mother, while Alicia's eldest son, Alberto Jr, works in the Banco Zaragozano bank.
The hard-nosed gossip is that Alberto Jr has persuaded his mother to catch the peak of Spain's stockmarket boom, sell up now and make a killing. Softer-focus whispering says that Alicia, always the less gregarious sister, is tired of making headlines and wants to withdraw from the limelight into rich obscurity.Reuse content