DGA758070: Main doorway and vestibule, Metropolitan Cathedral of St Mary of the Assumption and St Geminiano (UNESCO World Heritage List, 1997), Modena, Emilia-Romagna. Italy, 12th century. / Bridgeman Images

DGA757828: The Savior between St George and St Sebastian, fresco by Pietro Cavallini (ca 1240-ca 1330), apse, Church of San Giorgio (St George) in Velabro, Rome, Italy, 14th century / Bridgeman Images

DGA628181: Cross vaults of the canopy, upper chapel of the Holy Chapel, Paris, Ile-de-France, France, 13th century / Bridgeman Images

DGA628182: Angel, wooden relief from the canopy, upper chapel of the Holy Chapel, Paris, Ile-de-France, France, 13th century / Bridgeman Images

DGA756861: Glimpse of interior with baptismal font, by Guido Bigarelli (active 1244, died before 1257), and pulpit by Nicola Pisano (born between 1220 and 1225-died between 1278 and 1287), Baptistery of St John, Cathedral Square, Pisa, Tuscany. Detail. Italy. / Bridgeman Images

DGA912369: The Romanesque cloister of Aix Cathedral (11th-13th century), Aix-en-Provence, Provence-Alpes-Cote d'Azur, France / Bridgeman Images

DGA1131068: View of Metropolitan Cathedral-Basilica of Assumption of Our Lady of Valencia (13th-14th century) from bell tower, known as Miguelete or Micalet tower, Valencia, Valencian Community, Spain / Bridgeman Images

DGA924862: Cistercian Abbey of L'Epau (13th-14th century, restored in 1980), Yvre-l'Eveque, Pays de la Loire, France / Bridgeman Images

DGA924868: Capitular Hall (13th century), Cistercian Abbey of L'Epau (13th-14th century), Mans, Pays de la Loire, France / Bridgeman Images

DGA925791: Bas-relief of St Florian (18th century), detail from St Florian's Door (14th-17th century), historic centre of Krakow (Unesco World Heritage List, 1978), Lesser Poland Voivodeship, Poland / Bridgeman Images

DGA912343: Saint-Julien Cathedral (11th-16th century), Le Mans, Pays de la Loire, France / Bridgeman Images

DGA419514: Kiek in de Kok Tower, and walls of the Toompea Quarter (photo) / Bridgeman Images

DGA419516: Toompea Castle and Pikk Hermann Tower, Toompea Hill (photo) / Bridgeman Images

DGP421252: Richard I, the Lionheart, by Baron Carlo Marochetti, Old Palace Yard (photo) / Bridgeman Images

GRL5974071: The room of the Stolen Bucket: decorated recess, Ghirlandina Tower, Modena, Italy (photo) / Bridgeman Images

GRL5974160: The capital of King David or of dance and music, by Campionese Masters, XII - XIII century, east wall, Torresani Hall, Ghirlandina Tower, Modena, Italy (photo) / Bridgeman Images

GRL5974168: The capital of King David or of dance and music, by Campionese Masters, XII - XIII century, East, Wall, Torresani Hall, Ghirlandina Tower, Modena, Italy (photo) / Bridgeman Images

GRL5974169: The capital of King David or of dance and music, by Campionese Masters, XII - XIII century, East, Wall, Torresani Hall, Ghirlandina Tower, Modena, Italy (photo) / Bridgeman Images

GRL5974173: The capital of King David or of dance and music, by Campionese Masters, XII - XIII century, East, Wall, Torresani Hall, Ghirlandina Tower, Modena, Italy (photo) / Bridgeman Images

GRL5974179: The capital of King David or of dance and music, by Campionese Masters, XII - XIII century, East, Wall, Torresani Hall, Ghirlandina Tower, Modena, Italy (photo) / Bridgeman Images

DGA925180: Eldrad tilling soil at Ambilly, Provence, Detail from Stories of life of Saint Eldrad, Romanesque frescoes in Byzantine style, late 11th century, Chapel of Saint Eldrad and Saint Nicholas, Novalesa Abbey, Piedmont, Italy., Byzantine, (11th Century) / Bridgeman Images

DGA910825: Nave, Cathedral of Notre-Dame (13th century) (UNESCO World Heritage Site, 1981), Amiens, Picardy, France / Bridgeman Images

DGA628180: Cross vaults of the canopy, upper chapel of the Holy Chapel, Paris, Ile-de-France, France, 13th century / Bridgeman Images

DGA1134128: Syria - Aleppo. Historical Aleppo. UNESCO World Heritage List, 1986. Citadel, 13th century. Early evening lights (photo) / Bridgeman Images

DPS3254780: Kilkenny Castle; Kilkenny, County Kilkenny, Ireland (photo) / Bridgeman Images

KW6373398: Sanquesa, Navarre, Spain, Santa Maria Real (photo) / Bridgeman Images

DPS3249569: Gallarus Oratory, Dingle Peninsula, Co Kerry, Ireland (photo) / Bridgeman Images

DGA925338: Saint Liberata, detail of fresco, second half of the 14th century, Sanctuary of Santa Liberata, Cerreto Guidi, Tuscany, Italy. / Bridgeman Images

DPS3249844: St. Patrick's Cathedral, Dublin, Ireland (photo) / Bridgeman Images

DPS3503418: Ballindoon Friary, Co Sligo, Ireland; Dominican Monastery Founded In 1507 (photo) / Bridgeman Images

GNG4989494: Medina Azahara or AlZahra is the ruins of a vast, fortified Arab Muslim medieval palace-city built by Abd-ar-Rahman III al-Nasir, (912-961) Umayyad Caliph of Cordoba, and located on the western outskirts of Cordoba, Spain., Cordoba, Spain / Bridgeman Images

FBU4245758: Crenellations and loopholes at the top of the Medieval Castle of Kolossi, Built in the 13th century (1210) by the martial order of Hospitallers of Jerusalem The castle was rebuilt by Louis De Magnac, Grand Commander of the order of Hospitallers, in the 15th century (1454) Limassol region, Cyprus / Bridgeman Images

DPS3249413: Trim Castle, Co. Meath, Ireland (photo) / Bridgeman Images

DPS3255873: Limerick City, Co Limerick, Ireland, King John's Castle (photo) / Bridgeman Images

KW6373399: Sanquesa, Navarre, Spain, Santa Maria Real (photo) / Bridgeman Images

DGA1134161: Syria - Palmyra. Ancient Palmyra. UNESCO World Heritage List, 1980. Arab fortification Qal'at ibn Ma'an, 16th-17th century (photo) / Bridgeman Images