Earlier explorations by Caillé, Rohlfs and Lentz had brought a lot of data, but a vast swathe of the country had remained unknown. It’s precisely that part of Morocco that de Foucault had been exploring from June 1883 to may 1884.

During his long journey he took the following routes:

1. from Tangier where he disembarked (sailing from Algeria) he walked to Meknes (taking a route east of that taken by his predecessors) passing by Tetuan, Chaouen, Fez, Taza and Sefrou.

2. After crossing the middle Atlas to Beni-Mellal, he walked throughout the plain of Tadla and along the northern foothill of the high Atlas.

3. Then he crossed the high Atlas (east of the cols used by his predecessors) from Sidi Rahal to Ouarzazate through Tizi-n-Telouet.

4. Then he walked throughout the not yet explored part of the Moroccan Sahara which lies between the Anti-Atlas (north), the Draa river (east and south) and the Atlantic coast (west).

5. Back eastwards, he walked throughout the upper Draa and the Tafilalet valleys.

6. Eventually, he walked up the Moulouya valley (via Debdou) to end up in Oujda from which he crossed the border with Algeria where ended his round trip.

His journey was over 2000 km long. He would walk in daytime and write down at night secretly the information he had gathered in a “five square centimetres note book” using a “two centimetre long pencil” . His navigation and survey tools were a compass and a barometer. He disguised himself as a Rabbi and hired a genuine rabbi (Mardochée abi Serour) to accompany him in his journey. According to de Foucault, “Mardochée’s office had been to swear everywhere that I was a true rabbi, then to take care of the public relations with the indigenous (thus overshadowing me) and to forge the most fanciful stories whenever we had to give account of the use of my tools”

Regarding his disguising he wrote:

“There is a portion of Morocco where one can travel but it is small. The country is divided in two parts: the first one is under the sultan’s authority (blad el makhzen) where Europeans can go safely; the second one (four to five times larger that the first one) is populated by independent or rebellious tribes (bled es siba) where Europeans could not go but disguised. Thus five sixths of the country area are totally closed up to Christians; they could get in only by means of trick and by endangering their life. The reason for this intolerance is not religious fanaticism, it rather originates in a feeling common to all the natives: For them a European who travels in their country could not be anything but an emissary sent to explore their country; he comes to examine the place before the invasion; he is a spy and he must be killed for being a spy and not for being a no faithful (not believer)…they fear the conquistador more than they hate the Christian” .

And regarding his disguising as a Jew he wrote:

“Muslim or Jew? Should I put on the turban or the black bonnet (worn by Jews in Morocco) ? Caillé, Rohlfs and Lentz all had chosen the turban; I went for the bonnet. What urged me to this choice is the memory of all the troubles these travellers had been through because of their costumes; the obligation they had to adopt the same way of life than their fellow Muslims. Having genuine Muslims around permanently who were keeping a suspicious eye on my predecessors had certainly hampered their work…”

RECONNAISSANCE AU MAROC (1883 – 1884) that de Foucault wrote after his journey from 1885 to 1887, is a data mine about late XIX century Morocco especially the geography and local traditions of the regions he had been travelling through. He deserved the golden medal that La Société de Géographie de Paris awarded him. This book (published in October 1887 and republished in 1994 and 1939) in two volumes included also sketches (landscapes, costumes, arms, jewellery…) and 19 coloured maps. The explorations and the deep studies undertaken later (after France had achieved its goal in Morocco) by scientific and military missions have confirmed the accuracy of the data gathered by de Foucault and the relevance of his comments.