Technology & Infrastructure in the 9th century

15 sourced entries, 800 CE to 899 CE, oldest first. Also see Technology & Infrastructure across every century or everything else in the 9th century.

• 800Itza culture starts in Mesoamerica (840).source
• 800Ife, in present-day Nigeria, becomes an important urban center (approximate date).source
• 829The city of Wiesbaden (Germany) is first mentioned by Einhard, biographer of former emperor Charlemagne (approximate date).source
• 836The Basilica of St. Castor in Koblenz (Rhineland-Pfalz) is constructed.source
• 849In the Chinese capital city of Chang'an, an imperial prince is impeached during the Tang Dynasty from his position by officials at court, for erecting a building that obstructs a street in the northwesternmost ward in South Central Chang'an.source
• 854The German city of Ulm is first mentioned, in a document by Louis the German.source
• 860The Japanese alphabet Hiragana becomes more popular in Japan. The phonetic alphabet will be further simplified, and reduced to 51 basic characters (approximate date).source
• 860King Charles the Bald gives the order to build fortified bridges across the Seine and Loire Rivers, to protect Paris and the Frankish heartland against Viking raids. He hires the services of Weland, a Viking chieftain based on the Somme, to attack the Seine Vikings at their base on the Isle of Oissel. Weland besieges the Vikings—they offer him a huge bribe (6,000 pounds of silver) to let them escape.source
• 862March – Viking raiders led by Weland are trapped at Trilbardou Bridge (Northern France), and submit to King Charles the Bald. He and his family accept Christianity (they are baptised) before leaving Neustria.source
• 880The oldest known mention is made of the city of Dortmund (approximate date).source
• 883The first historic document (written by Regino of Prüm) mentions Duisburg.source
• 886King Alfred the Great of Wessex recaptures London from the Danish Vikings, and renames it Lundenburh. Slightly upstream from London Bridge, he builds a small harbor called Queenhithe. Alfred hands the town over to his son-in-law Æthelred, lord of Mercia. A street system is planned out in the town, with boundaries of 1,100 yards from east to west, and around 330 yards from north to south.source
• 895Autumn – King Alfred the Great blockades the Lea River and builds fortifications, trapping the Danish Vikings at Hertford. They abandon their longships and escape to Bridgnorth, located in the Severn Valley.source
• 896Summer – King Alfred the Great orders the building of English warships (almost twice as long as the longships) on the Itchen at Southampton, against the Danish Viking raiders in Wessex.source
• 899Winter – The Magyars turn back north towards the shores of the Venetian Lagoon. They pillage Chioggia and Pellestrina, and advance towards Malamocco. Their advance into the lagoon is checked by the assembly of the Venetian fleet under doge Pietro Tribuno, which defeats the Magyar's river crossing vessels at Albiola, causing them to pull back. This close call with the Magyars prompts the Venetians to initiate the fortification of the Rialto and the building of protective chains over the Grand Canal.source