Who is Ahmed el Aalj?

Scala Port. Bab Labhar. This monumental door build in blocks of stone is an icon for Essaouira.
All visitors entering the town from the port can see the inscription in arabic, carved in sandstone. It´s just on the triangular pediment surmounting the the door .
Translated in english:

“PRAISE TO ALLAH,
“This door , ordered by the glorious one of the kings, Sidi Mohammed , was built by its servetor Ahmed el Aalj”

(1184H/AD1770 )

In 1764 , Sultan Sidi Mohammad III engaged Théodore Cornut, a French architect, to design the new city. He worked three years on constructing the port and the Kasbah.
The sultan then let the english architect Ahmed el Aalj fulfill the project.
Laalej,Laalaj,alAji,al Aal,el Aalj - is the name given to all the persons who has converted to the islamic religion.
Qui est Ahmed Laalej, cet architecte anglais qui construisit la Porte de la Marine à Essaouira?

Sultan, سلطان‎ Sulṭān, is an islamic title used by certain muslim rulers. Lands ruled by a sultan are called a sultanate ( سلطنة‎). Mohammed V changed the style to Malik (king) on 14 August 1957, maintaining the subsidiary style Amir al-Mu´minin (Commander of the Faithful)
List of rulers of Morocco
History of Morocco
Kingdoms of Africa-Morocco

There is more knowledge in translating the inscription.
It starts with Alhamdulillah (الحمد لله) which is an arabic phrase meaning "Praise to God". In islam "the Hamdala" is used in special situations as: After sneezing, after waking up, response to "How are you? or in general every time a muslim desires to praise Allah. It is also used of many just as "thankfulness".

Traditionally arabic (islamic) writing begins with Bismillah al-rahman al-rahim ,

بسم الله الرحمن الرحيم

("In the name of God, most Gracious, most Compassionate")

This phrase constitutes the first verse of every "sura" (or chapter) of the Quran (except for the ninth sura), and is used in a number of contexts by Muslims.
Bismillah, بسملة ," in the name of God" is said before you start actions , like entering a house , eating or drinking or mounting your bike.