Complex sentence: William the Silent granted him amnesty, and it was on this occasion that he made his donation to the Frans Loenenhofje and in 1611 he had his painting made by Frans Hals as a memorial to this fact.
Split into simpler sentences: William the Silent granted him amnesty, and it was on this occasion that he made his donation to the Frans Loenenhofje. In 1611 he had his painting made by Frans Hals as a memorial to this fact.