In the late fourteenth and early fifteenth centuries Thessalonike was no longer the thriving city it used to be in the earlier part of the Palaiologan period. Subjected from the 1380s onwards to continuous Ottoman assaults and sieges, it was completely cut off by land. Because of the insecurity of the surrounding countryside, the fields outside the city walls remained untilled. Commercial activity was disrupted due to the city's isolation from its hinterland. As early as 1384 or 1385 Demetrios Kydones wrote that the suburbs of Thessalonike were devastated and that its once flourishing market was reduced to misery. This picture of economic decline is confirmed by archaeological evidence, which has revealed no sign of any major construction activity inside the city or in the surrounding countryside after 1380. In the subsequent generation Symeon described how Mehmed I interfered with the food supplies in 1417/18 and also lamented the breakdown of business within the city and the destruction of the lands outside during the siege of 1422–3. The city gates seem to have remained closed throughout the duration of the Ottoman threat. The only regular access that Thessalonians had to the outside world was by sea, and it was by this means that the provisioning of the city was maintained during these critical times.