Sheikh Hamdan bin Rashid Al Maktoum, a major horse racing figure for several decades, has died at the age of 75.
The older brother of Sheikh Mohammed, he was a significant investor in the sport in Britain and internationally though bloodstock and sponsorship.
Thousands of horses ran in his blue and white silks including Derby winners Nashwan and Erhaab under Willie Carson.
Top sprinter Battaash last year helped him become flat racing's champion owner in Britain for the sixth time.
Sheikh Mohammed posted a tribute on Twitter, in which he said: "May God have mercy on you, my brother, my support and my companion."
The deputy ruler of Dubai, he was known throughout racing simply as Sheikh Hamdan, with major breeding bases included the Shadwell Stud in Norfolk, England, the Derrinstown Stud in the Republic of Ireland and the Shadwell Farm in the United States.
He won numerous Classics and was successful with horses such as Dayjur, Unfuwain, Salsabil, Nayef, Taghrooda and Invasor.
Sheikh Hamdan was the United Arab Emirates minister of finance and 10 days of mourning have been announced in Dubai
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