Eastern Harbour of Alexandria – Pharos Debris & Caesareum Quays
Portus Magnus · Great Harbour of Alexandria · Caesareum Harbour · Palace Harbour
331 BCE – Medieval (331 BCE – 1422 CE harbour active)·Ptolemaic/Hellenistic / Roman / Byzantine·🇪🇬 Alexandria, Eastern Harbour (Portus Magnus) and Heptastadion foreshore, Egypt
About
About Eastern Harbour of Alexandria – Pharos Debris & Caesareum Quays
Alexandria's Portus Magnus: twin harbour system enclosed by Pharos island + 1260 m Heptastadion mole, comprising Emporium, Kibotos box-harbour, Diolkos slipways, Caesareum mole, Antirhodos queen basin and Pharos debris field. Coastal subsidence 6 m since 331 BCE, leaving Ptolemaic moles, breakwaters, lead-sheathed hulls and 3,500+ Pharos blocks at 4–12 m. CEAlex 1994– Empereur mapped 3,500 Pharos architectural elements (granite colossi, obelisk shafts of Seti I, sphinxes) toppled by quakes 1303/1323; Goddio side-scan located Caesareum avenue drowned. Alexandria harbour revolutionized Mediterranean grain trade. UNESCO 1996– JICA heritage management.
Why it mattersLargest Ptolemaic harbour complex surviving underwater; Pharos block assemblage reconstitutes lighthouse architecture and quantifies 6 m subsidence of Nile delta promontory.
Open questions
Mysteries & theories
Mysteries
- 01Reconstruction of Pharos tier heights from block scarp
- 02Mole chronology – Heptastadion single-phase or two-phase Hellenistic–Roman?
Theories
- 01Lead ingot hull linings imply Roman pozzolana mole repairs after AD 365 vs original Ptolemaic rough
Theories are interpretations, not findings. The seal above tells you how much scholarly weight the place carries.
History
How it came to be
- Built
- Dinocrates, Sostratus, Caesareum architects
- Period
- 331 BCE – Medieval (331 BCE – 1422 CE harbour active)
- Culture
- Ptolemaic/Hellenistic / Roman / Byzantine
- Builders
- Ptolemaic
- Purpose
- Imperial grain port, naval base, lighthouse approach, Palace naval dock
- Abandoned
- Progressively silted + 365/741/1111/1303 quakes; 1422 mole collapse
- Rediscovered
- Napoleonic Description Égypte 1809; Empereur 1994 CEAlex, Goddio 1998
- Excavation
- Excavation ongoing
331 BCE
Heptastadion mole built, two harbours defined
280 BCE
Pharos lighthouse completed by Sostratus
30 BCE
Caesareum harbour built for Octavian cult
365 CE
365 Crete quake subsides Heptastadion 2 m
1994–96
Empereur maps 3500 Pharos blocks; Goddio maps Caesareum mole
On the ground
Structures & features
31.2020° N · 29.8850° E · -4 m · 3 mapped features
Pharos debris field (foot of Qaitbey)
lighthouse debris3500 blocks including 2 Seti I obelisks at 6–12 m
31.2140° N · 29.8855° ECaesareum submerged mole
harbourCaesareum avenue continuation under 4 m silt
31.2025° N · 29.8880° EHeptastadion axis
causewayMole axis traceable on harbour floor
31.2030° N · 29.8820° E