Germany's once richest man Theo was a reclusive

Exceedingly rich, excessively thrifty, and obsessively reclusive Theodor Paul Albrecht co-founded, with his elder brother, Karl, the discount supermarket chain Aldi, so successfully that he became, after his brother, the richest man in Germany. But this came at a great price. After his sensational kidnapping in 1971 and his release on the payment of a ransom, he was barely ever seen in public again.

Born in the city of Essen, in the Ruhr Valley of West Germany, his early life was tough, which may explain his life-long parsimony. His father was forced to abandon his work as a miner due to emphysema, and his mother opened a small grocery to sustain the family. Both brothers were conscripted; Theo worked in supplies with Rommel's Afrika Korps. After the war, Karl and Theo began opening a succession of grocery stores. Their policy was "best quality, lowest price". By 1960 they had 300 stores in Germany, and the following year they named their company Aldi, a contraction of Albrecht discount.

In the late 1960s, the brothers decided to divide their empire, prompted by a disagreement over the sale of cigarettes at the check-out. Karl believed it would attract shoplifters and affect profits. Karl assumed control of Aldi-Sud, Theo Aldi-Nord, with agreement that they would not compete - at home, or abroad. In 1971 a Dusseldorf lawyer, in strife with gambling debts, kidnapped Theo at gunpoint and held him in his legal office for 17 days. So unprepossessing did his captive look, that the kidnapper at first demanded to see his ID. The kidnapping lasted longer because Theo haggled over the sum. A ransom of £1.5 million was paid and Theo released. The lawyer was captured and half the ransom recovered. Theo later claimed a tax deduction for the ransom on the basis it was a business expense.

The brothers' frugality was legion. They would use pencil stubs to take notes, and remonstrated with executives presenting plans for a store in the Netherlands, saying the paper on which they were written was "too thick". Aldi's pile-it-high, sell-it-cheap approach worked brilliantly. Aldi-Nord expanded into Europe and the United States, where it had acquired the Trader Joe's grocery chain in 1979. Aldi-Sud moved into the UK and Australia. By 2009, the group had almost 9,400 stores and a turnover of more than £40 billion. Forbes magazine estimated Theo's wealth in March 2010 at £10.7 billion, making him the 31st richest man in the world. He had been ninth richest in 2009, an indication of falling profits and the increasing success of other retailers, including Lidl and Real.

Both brothers lived on the remote North Sea island of Foehr. The last known photograph of Theo was taken in 1988 and it is claimed that in 65 years he submitted to only three interviews. For some years the group was managed by family-appointed executives. Succession is unclear. Although Theo's two sons, Theo and Berthold, worked for Aldi-Nord, neither occupied senior positions. Both sons and their uncle, Karl, survive Theo, who was 88.

Theodor Paul Albrecht was born 28 March 1922, and died 24 July 2010. * The National