function Imagen_Aleatoria() {

var cc1 = Math.floor(Math.random() * collage1.length)
var cc2 = Math.floor(Math.random() * collage2.length)
var cc3 = Math.floor(Math.random() * collage3.length)
if (cc1 == 0) { cc1 = 1 } 
if (cc2 == 0) { cc2 = 1 } 
if (cc3 == 0) { cc3 = 1 } 

	 document.write ('<span class="imagenportada"><img src="'+collage1[cc1]+'" width="124" height="124" alt="'+pie1[cc1]+'" border="0" /></span>');
	 document.write ('<span class="imagenportada"><img src="'+collage2[cc2]+'" width="124" height="124" alt="'+pie2[cc2]+'" border="0" /></span>');
	 document.write ('<span class="imagenportada"><img src="'+collage3[cc3]+'" width="124" height="124" alt="'+pie3[cc3]+'" border="0" /></span>');

}

// 1
var collage1=new Array(); 
collage1[1] = '/seccion/historia/graf/collage1a.jpg';
collage1[2] = '/seccion/historia/graf/collage1b.jpg';


var pie1=new Array(); 
pie1[1] = 'Mosaico de Itálica';
pie1[2] = 'Ladrillo cristiano';

// 2
var collage2=new Array(); 
collage2[1] = '/seccion/historia/graf/collage2a.jpg';
collage2[2] = '/seccion/historia/graf/collage2b.jpg';

var pie2=new Array(); 
pie2[1] = 'Monasterio de Ripoll';
pie2[2] = 'San Juan de Duero';

// 3
var collage3=new Array(); 
collage3[1] = '/seccion/historia/graf/collage3a.jpg';
collage3[2] = '/seccion/historia/graf/collage3b.jpg';

var pie3=new Array(); 
pie3[1] = 'Mezquita de Córdoba';
pie3[2] = 'Monasterio de Batalha';

Imagen_Aleatoria()