Erwin I von Gleichen

Erwin I (c. 1040 – c. 1116) is the earliest known member of the comital house of Gleichen in Thuringia. He first appears in charters in 1099 as count at Tonna and is named count in Thuringia in 1114. Late in life he became a monk at Reinhardsbrunn Abbey.

By his wife Helinburg, daughter of Count Beringer I of Lohra, he left two sons who carried the line forward, Ernst I of Tonna and Lambert I.