This is another gold coin from Sultan Alaudin Riayat Shah era. He was the son of the last Malacca Sultan, Sultan Mahmud Shah who fled from Malacca after the invasion of Portugese. He became the first ruler of Johor Empire in 1527CE.he set up his capital at Johor Lama situated on the Johor river. He promoted foreign trade and was able to attract a fair amount of commerce. However Johor was captured by Acheh in 1564CE and became its vassal state until the collapse of the Acheh Empire in 1641CE.
Looking at the Arabic calligraphy used, its quite tricky as the calligraphy is compressed to fit on the coin face. However it has the resemblance to Thuluth & Sini. Or probably this is how Malay calligraphy was derived. I noticed also similar calligraphy was used on the tombstone ( pic edited from artmelayu.bs) of the same Sultan in Johor except all vertical alphabets were elongated to fill the column.
As for this coin, there are some errors in the words used.
Notice the Sultan is written ثلطان instead of سلطان
The word choice mu'min for singular is used instead of mu'minin for plural
My other coin is in below link
Sultan Alauddin I
Sultan Alauddin I
Octagonal gold coin ( kupang) under the rule of Johor Sultan Alaudin Riayat Shah 1 ( 1527-1564AD).
Obv: Sultan Alaudin سلطان علاالدين
Rev: Khalifatul Mukmin Shah خليفة الموْمن شاه
weight : 0.64gm
Dim : 12mm
Rarity : RR ( ref SS2)