The Battle of Grand Gulf was fought on April 29, 1863, during th: Old English is essentially a distinct language from Modern English and is virtually impossible for 21st-century unstudied English-speakers to understand. Its grammar was similar to that of modern German: nouns, adjectives, pronouns, and verbs had many more inflectional endings and forms, and word order was much freer than in Modern English. Modern English has case forms in pronouns (he, him, his) and has a few verb inflections (speak, speaks, speaking, spoke, spoken), but Old English had case endings in nouns as well, and verbs had more person and number endings.[40][41][42] Its closest relative is Old Frisian, but even some centuries after the Anglo-Saxon migration, Old English retained considerable mutual intelligibility with other Germanic varieties. Even in the 9th and 10th centuries, amidst the Danelaw and other Viking invasions, there is historical evidence that Old Norse and Old English retained considerable mutual intelligibility,[43] although probably the northern dialects of Old English were more similar to Old Norse than the southern dialects. Theoretically, as late as the 900s AD, a commoner from certain (northern) parts of England could hold a conversation with a commoner from certain parts of Scandinavia. Research continues into the details of the myriad tribes in peoples in England and Scandinavia and the mutual contacts between them.[43]