This study is the first to successfully address the identification of the botanical components of a garden in the 2000-year-old palatial courtyard of Herod the Great's Promontory Palace in Caesarea Maritima. Based on the extraction and identification of fossil pollen grains, we were able to reconstruct at least part of the garden's flora, which, we argue, could only have grown within the confines of a garden of this splendid seaside palace which was protected architecturally from salty sea spray. The palynological spectrum included, among other taxa, high percentages of Cupressaceae pollen (cypress) as well as pollen of the non-local tree Corylus sp. (hazelnut), which was most probably introduced as an ornamental from the northeast Mediterranean or from Italy. These trees appear to have been accompanied by other ornamental plants (e.g. Salvia and various Rosaceae plants). The choice of flora to be planted in the garden is consistent with our knowledge of prestige Roman gardens dated to Herod's time. This exceptional and magnificent palace, with its luxurious architectural features and its impressive, well-maintained garden, symbolized the power and the abilities of King Herod, the greatest builder in ancient Jewish history.