Gerlach V of Isenburg-Limburg (died April 14, 1355), also called Gerlach II "the Elder" of Limburg, was Count of Isenburg-Limburg. He reigned between 1312 and 1355 as Lord of Limburg an der Lahn, and the head of the House of Limburg. The chronicler Tilemann Elhen von Wolfhagen describes him, in his pre-1402 Limburger Chronicle, as a virtuous nobleman and a bright poet in German and Latin. Life Gerlach V's reign began on the death of his father John I in 1312. Under Gerlach II, the city of Limburg an der Lahn achieved its highest medieval flowering. The chronicler Tilemann Elhen reported that, at the height of its prosperity, the city could summon over 2,000 weapons-capable citizens. Because of the marriage policies of his predecessors, Gerlach could rely on family relationships with most of the noble families in the vicinity. Gerlach acted as an arbitrator in several disputes between neighboring noble families. He was, like his father, chairman of the arbitrating body of the Ottonian line of the House of Nassau. In 1329 he also mediated a settlement between Gerlach I of Nassau-Wiesbaden-Idstein-Weilburg and William of Katzenelnbogen. The following year, he issued an arbitral award between William and John II of Katzenelnbogen. In 1331 Gerlach joined the Landfriedensbündnis (country peace alliance) of the Archbishop of Trier, Baldwin of Luxembourg. In 1339, he mediated a settlement between Gottfried of Diez and the House of Nassau. The city of Limburg was strategically important due to its location on the main trade route from Cologne to Frankfurt. This led to frequent conflicts with neighbouring lordships and made the city a target of robber barons. As a result, the city was heavily fortified by the Counts of Limburg. In 1315, near the beginning of his reign, Gerlach built towers around the city. He laid out suburbs in front of the Diez and Frankfurt Gates and the approach to the bridge. The suburbs of Limburg extended beyond the limits of his dominion, leading to regular disputes with the neighboring Counts of Diez. Under Gerlach’s administration, numerous construction projects, some of them started by his father, were completed in Limburg. These included the stone bridge over the Lahn River (1315) and the new church of the Franciscan monastery (1320, today the city church). He allowed the Williamite monastery founded on the island in the Lahn in 1312 to relocate in 1317 to a new building in the