Bronze Age The first traces of human habitation of the island are from the late
Bronze Age, 900 to 700 BC. A
bronze axe head was discovered on the island in 1988, between the island's farmhouse and West Beach.
Sub-Roman In the
sub-Roman period of the 5th-6th century AD, it became a retreat for
Saint Cadoc, who lived on the island as a hermit for seven years. His friend,
Saint Gildas born in the
Kingdom of Strathclyde but educated at the
College of Theodosius (
Cor Tewdws) in the
Kingdom of Gwent, lived at the same time on nearby
Steep Holm, and the two sometimes met up for prayers. Gildas eventually left the island to become
Abbot of Glastonbury. In June 1815, a Dr Thomas Turner visited Flat Holm in a small boat and was stranded for a week due to high winds. He discovered two Christian graves located close together in a field northeast of the island's present farmhouse; one grave had been opened and contained a male skeleton. The open grave's headstone was made of
purbeck marble and engraved with a
Celtic cross, but had since broken in two. A second disturbed grave, also marked with a headstone, was found to the southeast and contained a coffin constructed with iron bolts. Inside the coffin were two skeletons which had been doused in lime, indicating that the occupants had probably died from a
contagious disease.
Middle Ages Anglo-Saxons called the island
Bradanreolice.
Reolice derives from an Irish word meaning churchyard or graveyard, alluding to the belief that the island had religious significance as a place of burial to people at the time. Records indicate that a
Viking fleet from the south of
Brittany led by two earls,
Ottir (
Oter) and
Hroald (possibly Ottir's king
Ragnall), took refuge on the island following their defeat by the
Saxons at
Watchet. The
Anglo-Saxon Chronicle records that in 1067,
Gytha Thorkelsdóttir, mother of
Harold II, the last Anglo-Saxon king of England, stayed on the island before travelling to
St Omer in France after the
Norman conquest of England. After the invasion,
Robert Fitzhamon formed the
Shire of Glamorgan in Wales proper, with
Cardiff Castle at the centre of his new domain. Flat Holm came within the parish boundary of St Mary's, one of Cardiff's two parish churches, and was kept as a hereditary property of the
Norman Lords of Glamorgan. A survey by archaeologist Howard Thomas in 1979 unearthed a number of medieval
potsherds in the vicinity of the farmhouse and found evidence of continuous occupation of the island including
middens containing numerous animal bones along with oyster and
cockle shells. Fragments of green glazed jugs and flagons from the late 12th to 13th century and shards of pottery from the 14th century were also found on the island. The presence of Pennant
sandstone roofing tiles and a fragment of a 14th-century glazed ridge tile indicate the existence of a substantial medieval building, possibly a chapel, demolished when the present farmhouse was constructed. Property records from 1542 show that King
Henry VIII granted a lease to farm the island to a gentleman by the name of Edmund Tournor. His family remained on Flat Holm until the end of the 17th century when the lease passed to Joseph Robins. Although Flat Holm was in full view of both the Welsh and English coasts, customs authorities were powerless to act as they had no boat to take them to the island. According to tradition, a small cave in the east cliff at Flat Holm was used for the storage of contraband, mainly tea and brandy.
19th century – Seafarer's Mission and Marconi 's equipment on Flat Holm, May 1897 In 1835, clergyman
John Ashley from
Clevedon voluntarily ministered to the population of the island. Ashley created the Bristol Channel Mission in order to serve seafarers on the 400 sailing vessels which used the Bristol Channel. The mission would later become the
Mission to Seafarers, which still provides ministerial services to sailors in over 300 ports. On 13 May 1897, a 22-year-old Italian inventor named
Guglielmo Marconi, assisted by a Cardiff Post Office engineer named George Kemp, transmitted the first
wireless signals over open sea from Flat Holm to
Lavernock Point near
Penarth, Wales. Having failed to interest the Italian government in his project, Marconi had brought his
telegraphy system to Britain. Here he met Welshman
William Preece who was at that time Chief Engineer of the
General Post Office and a major figure in the field. Marconi and Preece erected a high transmitting mast on Flat Holm as well as a receiving mast at Lavernock Point. The first trials on 11 May and 12 failed. On 13 May, the mast at Lavernock was raised to and the signals were received clearly. The message sent by
Morse Code was "Are you ready"; the original paper Morse slip, signed by both Marconi and Kemp, is now in the
National Museum of Wales. On 23 October 1817, a British
sloop,
William and Mary, foundered after hitting the three rocky islets known as
The Wolves which are not far from near Flat Holm. The ship was en route from Bristol to
Waterford and sank within 15 minutes. The
ship's mate, John Outridge, and two sailors made off in the only lifeboat. 15 survivors were later rescued, having clung to the ship's rigging, but 54 other passengers were lost. 50 of the bodies were recovered from the ship and were buried on Flat Holm. In 1938 the
steamship Norman Queen ran ashore on Flat Holm but was refloated, ==Geography==