Complex sentence: It was formed in 2006 through a merger of the listed British high street pharmacist Boots Group and the pan-European wholesale and retail pharmacy groupAlliance UniChem, and was initially a British plc listed on the London Stock Exchange.
Split into simpler sentences: It was formed in 2006 through a merger of the listed British high street pharmacist Boots Group and the pan-European wholesale and retail pharmacy group Alliance UniChem. Alliance Boots was initially a British plc listed on the London Stock Exchange.