Please check my letter and give me your recommendations

Please give me your best oppinion and/or recommendations about the following invitation letter lines as it will be sent to international guests for an important event of the company I work for and I would like to give the best impression. Thank you very much Guys!!

On (date) 2008 (company name) will celebrate its fiftieth anniversary and in order to commemorate such a special moment, we have the pleasure of inviting you to a ceremony that will be held in Mexico City at the (place name) of The Chapultepec Castle at (hour) hrs.

We will be honored by your presence in this memorable event, therefore please be so kind to confirm your attendance to the following numbers: (phone numbers).