Melvyn Bragg and guests discuss the republic that emerged from the union of the Kingdom of Poland and Grand Duchy of Lithuania in the 14th Century. At first this was a personal union, similar to that of James I and VI in Britain, but this was formalised in 1569 into a vast republic, stretching from the Baltic to the Black Sea. Kings and princes from across Europe would compete for parliament to elect them King and Grand Duke, and the greatest power lay with the parliaments. When the system worked well, the Commonwealth was a powerhouse, and it was their leader Jan Sobieski who relieved the siege of Vienna in 1683, defeating the Ottomans. Its neighbours exploited its parliament's need for unanimity, though, and this contributed to its downfall. Austria, Russia and Prussia divided its territory between them from 1772, before the new, smaller states only emerged in the 20th Century. The image above is Jan III Sobieski (1629-1696), King of Poland and Grand Duke of Lithuania, at the Battle of Vienna 1683, by Marcello Bacciarelli (1731-1818) With Robert Frost The Burnett Fletcher Chair of History at the University of Aberdeen Katarzyna Kosior Lecturer in Early Modern History at Northumbria University And Norman Davies Professor Emeritus in History and Honorary Fellow of St Antony’s College, University of Oxford Producer: Simon Tillotson

Melvyn Bragg and guests discuss the race to build an atom bomb in the USA during World War Two. Before the war, scientists in Germany had discovered the potential of nuclear fission and scientists in Britain soon argued that this could be used to make an atom bomb, against which there could be no defence other than to own one. The fear among the Allies was that, with its head start, Germany might develop the bomb first and, unmatched, use it on its enemies. The USA took up the challenge in a huge engineering project led by General Groves and Robert Oppenheimer and, once the first bomb had been exploded at Los Alamos in July 1945, it appeared inevitable that the next ones would be used against Japan with devastating results. The image above is of Robert Oppenheimer and General Groves examining the remains of one the bases of the steel test tower, at the atomic bomb Trinity Test site, in September 1945. With Bruce Cameron Reed The Charles A. Dana Professor of Physics Emeritus at Alma College, Michigan Cynthia Kelly Founder and President of the Atomic Heritage Foundation And Frank Close Emeritus Professor of Theoretical Physics at the University of Oxford and a Fellow of Exeter College, Oxford Producer: Simon Tillotson

Melvyn Bragg and guests discuss the Greek writer known as the father of histories, dubbed by his detractors as the father of lies. Herodotus (c484 to 425 BC or later) was raised in Halicarnassus in modern Turkey when it was part of the Persian empire and, in the years after the Persian Wars, set about an inquiry into the deep background to those wars. He also aimed to preserve what he called the great and marvellous deeds of Greeks and non-Greeks, seeking out the best evidence for past events and presenting the range of evidence for readers to assess. Plutarch was to criticise Herodotus for using this to promote the least flattering accounts of his fellow Greeks, hence the 'father of lies', but the depth and breadth of his Histories have secured his reputation from his lifetime down to the present day. With Tom Harrison Professor of Ancient History at the University of St Andrews Esther Eidinow Professor of Ancient History at the University of Bristol And Paul Cartledge A. G. Leventis Senior Research Fellow at Clare College, University of Cambridge Producer: Simon Tillotson

Melvyn Bragg and guests discuss the life and ideas of one of the great historians, best known for his History of the Decline and Fall of the Roman Empire (published 1776-89). According to Gibbon (1737-94) , the idea for this work came to him on 15th of October 1764 as he sat musing amidst the ruins of Rome, while barefooted friars were singing vespers in the Temple of Jupiter. Decline and Fall covers thirteen centuries and is an enormous intellectual undertaking and, on publication, it became a phenomenal success across Europe. The image above is of Edward Gibbon by Henry Walton, oil on mahogany panel, 1773. With David Womersley The Thomas Wharton Professor of English Literature at St Catherine’s College, University of Oxford Charlotte Roberts Lecturer in English at University College London And Karen O’Brien Professor of English Literature at the University of Oxford Producer: Simon Tillotson

Melvyn Bragg and guests discuss Charles Booth's survey, The Life and Labour of the People in London, published in 17 volumes from 1889 to 1903. Booth (1840-1916), a Liverpudlian shipping line owner, surveyed every household in London to see if it was true, as claimed, that as many as a quarter lived in poverty. He found that it was closer to a third, and that many of these were either children with no means of support or older people no longer well enough to work. He went on to campaign for an old age pension, and broadened the impact of his findings by publishing enhanced Ordnance Survey maps with the streets coloured according to the wealth of those who lived there. The image above is of an organ grinder on a London street, circa 1893, with children dancing to the Pas de Quatre With Emma Griffin Professor of Modern British History at the University of East Anglia Sarah Wise Adjunct Professor at the University of California And Lawrence Goldman Emeritus Fellow in History at St Peter’s College, University of Oxford Producer: Simon Tillotson