Complex sentence: By 1308 the resources of the Gallipoli peninsula were exhausted and the company headed west towards Greece, reestablishing themselves on the peninsula of Kassandra near present day Halkidiki, from where they attacked and pillaged the locality, including Mount Athos monastery.
Split into simpler sentences: By 1308 the resources of the Gallipoli peninsula were exhausted and the company headed west towards Greece, reestablishing themselves on the peninsula of Kassandra near present day Halkidiki. From there they attacked and pillaged the locality, including Mount Athos monastery.